Water filtration membrane device and method of manufacture

Abstract

Water filtration compositions, membranes, devices and methods of manufacture including graphene oxide having hydrophilic functionality. A composition including graphene oxide having an average particle size of no greater than about 1 micron and an oxygen atom percentage of at least about 30% is disclosed, as are membranes including the composition, water permeable devices including the membranes, methods of using the composition to make the membranes, and several methods of making the composition.

Description

[0001] Divisional Statement

[0002] This application is a divisional application of the Chinese application with the application number 201980055329.9 and the title “Water filtration membrane device and method of making” filed on August 21, 2019. TECHNICAL FIELD

[0003] The present disclosure relates generally to devices and methods for water treatment, and more particularly, to water filtration membranes, devices, and methods of manufacture including graphene oxide having hydrophilic functional groups. BACKGROUND

[0004] Membrane technology is favored over other technologies in water treatment applications such as disinfection, distillation, or media filtration because it generally does not require chemical additives, heat input, or regeneration of the consumed media. However, the operating cost of membrane technology is relatively high due to the short service time of the membrane and the rapid performance decay caused by membrane fouling. When the pores in the membrane are blocked or clogged, or when a polarization concentration layer or a filter cake layer is formed on the surface of the membrane, the water flux through the membrane will be significantly reduced.

[0005] The antifouling properties of conventional water filtration membranes remain to be improved. Due to the hydrophobicity of the membrane material, contaminants or bio-organisms can easily adhere to the membrane surface. The antifouling can be effectively prevented by adding graphene oxide having hydrophilic functional groups to the water filtration membrane by increasing the hydrophilicity of the membrane. Graphene oxide obtained by conventional methods is usually too large in size or not uniformly dispersed, resulting in uneven distribution of the pore size and / or porosity of the membrane. In addition, the hydrophilic functional groups included in the graphene oxide prepared by conventional processes are insufficient, which limits the hydrophilicity of the membrane. These factors are major bottlenecks that need to be addressed before water filtration membranes integrated with graphene can achieve commercial value. SUMMARY

[0006] Several new methods of synthesizing oxygen-rich graphene oxide, which can be single-layer graphene oxide including a high percentage of hydrophilic functional groups, are disclosed. Methods of mixing and dispersing the oxygen-rich graphene oxide into various water filtration membrane products with high uniformity are also disclosed. These methods can significantly improve the hydrophilicity and water flux of the membranes. They can also improve the antifouling and anti-biofouling properties of the membranes, thereby extending the cleaning time of the membranes and reducing the cost of water treatment. In addition, the method using saccharides as raw materials provides an environmentally friendly, impurity-free, and low-cost method of large-scale production of graphene oxide.

[0007] Compositions, membranes, devices, and methods of making water filtration systems including graphene oxide are also disclosed.

[0008] In one aspect, a composition comprising graphene oxide is disclosed, wherein the graphene oxide has an average particle size of no more than about 2 microns and an oxygen atom percentage of at least about 30%. In some embodiments, the graphene oxide has an average particle size of no more than about 1 micron. In some embodiments, the graphene oxide has an average particle size of about 0.001 microns to 2 microns. In some embodiments, the graphene oxide has an average particle size of at least about 0.001 microns. In some embodiments, the graphene oxide has an average particle size of at most about 2 microns. In some embodiments, the graphene oxide has an average particle size of at most about 1.5 microns. In some embodiments, the graphene oxide has an average particle size of at most about 1 micron. In some embodiments, the graphene oxide has an average particle size of at most about 0.5 microns. In some embodiments, the graphene oxide has an average particle size of at most about 0.2 microns. In some embodiments, the graphene oxide has an average particle size of at most about 0.1 microns. In some embodiments, the graphene oxide has an average particle size of at most about 0.05 microns. In some embodiments, the graphene oxide has an average particle size of at most about 0.01 microns.In some embodiments, the average particle size of the graphene oxide is about 2 microns to about 1.5 microns, about 2 microns to about 1 micron, about 2 microns to about 0.5 microns, about 2 microns to about 0.2 microns, about 2 microns to about 0.1 microns, about 2 microns to about 0.05 microns, about 2 microns to about 0.01 microns, about 2 microns to about 0.005 microns, about 2 microns to about 0.001 microns, about 1.5 microns to about 1 micron, about 1.5 microns to about 0.5 microns, about 1.5 microns to about 0.2 microns, about 1.5 microns to about 0.1 microns, about 1.5 microns to about 0.05 microns, about 1.5 microns to about 0.01 microns, about 1.5 microns to about 0.005 microns, about 1.5 microns to about 0.001 microns, about 1 micron to about 0.5 microns, about 1 micron to about 0.2 microns, about 1 micron to about 0.1 microns, about 1 micron to about 0.05 microns, about 1 micron to about 0.01 microns, about 1 micron to about 0.005 microns, about 1 micron to about 0.001 microns, about 0.5 microns to about 0.2 microns, about 0.5 microns to about 0.1 microns, about 0.5 microns to about 0.05 microns, about 0.5 microns to about 0.01 microns, about 0.5 microns to about 0.005 microns, about 0.5 microns to about 0.001 microns, about 0.2 microns to about 0.1 microns, about 0.2 microns to about 0.05 microns, about 0.2 microns to about 0.01 microns, about 0.2 microns to about 0.005 microns, about 0.2 microns to about 0.001 microns, about 0.1 microns to about 0.05 microns, about 0.1 microns to about 0.01 microns, about 0.1 microns to about 0.005 microns, about 0.1 microns to about 0.001 microns, about 0.05 microns to about 0.01 microns, about 0.05 microns to about 0.005 microns, about 0.05 microns to about 0.001 microns, about 0.01 microns to about 0.005 microns, about 0.01 microns to about 0.001 microns, or about 0.005 microns to about 0.001 microns. In some embodiments, the average particle size of the graphene oxide is about 2 microns, about 1.5 microns, about 1 micron, about 0.5 microns, about 0.2 microns, about 0.1 microns, about 0.05 microns, about 0.01 microns, about 0.005 microns, or about 0.001 microns. In some embodiments, the average particle size of the graphene oxide is no greater than about 100 nanometers. In some embodiments, the average particle size of the graphene oxide is about 10 nanometers to about 100 nanometers.

[0009] In some embodiments, the percentage of oxygen atoms of the graphene oxide is about 30% to about 70%. In some embodiments, the percentage of oxygen atoms of the graphene oxide is at least about 30%. In some embodiments, the percentage of oxygen atoms of the graphene oxide is at most about 70%. In some embodiments, the percentage of oxygen atoms of the graphene oxide is about 30% to about 35%, about 30% to about 40%, about 30% to about 45%, about 30% to about 50%, about 30% to about 55%, about 30% to about 60%, about 30% to about 65%, about 30% to about 70%, about 35% to about 40%, about 35% to about 45%, about 35% to about 50%, about 35% to about 55%, about 35% to about 60%, about 35% to about 65%, about 35% to about 70%, about 40% to about 45%, about 40% to about 50%, about 40% to about 55%, about 40% to about 60%, about 40% to about 65%, about 40% to about 70%, about 45% to about 50%, about 45% to about 55%, about 45% to about 60%, about 45% to about 65%, about 45% to about 70%, about 50% to about 55%, about 50% to about 60%, about 50% to about 65%, about 50% to about 70%, about 55% to about 60%, about 55% to about 65%, about 55% to about 70%, about 60% to about 65%, about 60% to about 70%, or about 65% to about 70%. In some embodiments, the graphene oxide has a percentage of oxygen atoms of about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, or about 70%. In some embodiments, the percentage of oxygen atoms is at least 35%. In some embodiments, the percentage of oxygen atoms is about 35% to about 50%.

[0010] In some embodiments, the graphene oxide has an absorbance level at a wavelength of 230 nanometers that is lower than graphene oxide having an average particle size greater than 1 micron. For example, the graphene oxide can have an absorbance level at a wavelength of 230 nanometers that is at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% lower than the graphene oxide having an average particle size greater than 1 micron. In some embodiments, the graphene oxide has an absorbance level at a wavelength of 230 nanometers that is lower than graphene oxide having an average particle size greater than 2 microns. For example, the graphene oxide can have an absorbance level at a wavelength of 230 nanometers that is at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% lower than the graphene oxide having an average particle size greater than 2 microns. In some embodiments, the graphene oxide has an absorbance level at a wavelength of 230 nanometers that is lower than graphene oxide having an average particle size greater than 5 microns. For example, the graphene oxide can have an absorbance level at a wavelength of 230 nanometers that is at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% lower than the graphene oxide having an average particle size greater than 5 microns. In some embodiments, the graphene oxide has an absorbance level at a wavelength of 230 nanometers that is lower than graphene oxide having an average particle size greater than 10 microns. For example, the graphene oxide can have an absorbance level at a wavelength of 230 nanometers that is at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% lower than the graphene oxide having an average particle size greater than 10 microns.

[0011] In some embodiments, the graphene oxide has an absorbance level at a wavelength of 230 nanometers that is lower than graphene oxide having a percent oxygen atoms less than 30%. For example, the graphene oxide can have an absorbance level at a wavelength of 230 nanometers that is at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% lower than the graphene oxide having a percent oxygen atoms less than 30%. In some embodiments, the graphene oxide has an absorbance level at a wavelength of 230 nanometers that is lower than graphene oxide having a percent oxygen atoms less than 20%. For example, the graphene oxide can have an absorbance level at a wavelength of 230 nanometers that is at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% lower than the graphene oxide having a percent oxygen atoms less than 20%. In some embodiments, the graphene oxide has an absorbance level at a wavelength of 230 nanometers that is lower than graphene oxide having a percent oxygen atoms less than 10%. For example, the graphene oxide can have an absorbance level at a wavelength of 230 nanometers that is at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% lower than the graphene oxide having a percent oxygen atoms less than 10%.

[0012] In some embodiments, the graphene oxide has an absorbance level at a wavelength of 230 nanometers that is lower than graphene oxide made with a lesser amount of H2SO4. For example, the graphene oxide can have an absorbance level at a wavelength of 230 nanometers that is at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% lower than graphene oxide made using a lesser amount of sulfuric acid.

[0013] In some embodiments, the composition further comprises sulfuric acid. In some embodiments, the composition further comprises an oxidizing agent. In some embodiments, the oxidizing agent comprises oxygen (O2), ozone (O3), hydrogen peroxide (H2O2), Fenton's reagent, fluorine (F2), chlorine (Cl2), bromine (Br2), iodine (I2), nitric acid (HNO3), sulfuric acid (H2SO4), peroxodisulfuric acid (H2S2O8), peroxymonosulfuric acid (H2SO5), chlorite, chlorate, perchlorate, hypochlorite, bleach (NaClO), chromic acid, dichromic acid, chromium trioxide, pyridinium chlorochromate (PCC), permanganate, sodium perborate, nitrous oxide (N2O), nitrogen dioxide (NO2), dinitrogen tetroxide (N2O4), potassium nitrate (KNO3), sodium bismuthate, or any combination thereof. In some embodiments, the oxidizing agent comprises hydrogen peroxide. In some embodiments, the oxidizing agent comprises potassium permanganate.

[0014] In some embodiments, the composition further comprises an organic solvent. In some embodiments, the organic solvent comprises a nonpolar solvent, a polar aprotic solvent, a polar protic solvent, or any combination thereof. In some embodiments, the nonpolar solvent comprises pentane, cyclopentane, hexane, cyclohexane, benzene, toluene, 1,4-dioxane, chloroform, diethyl ether, dichloromethane (DCM), or any combination thereof. In some embodiments, the polar aprotic solvent comprises tetrahydrofuran (THF), ethyl acetate, acetone, dimethylformamide (DMF), acetonitrile (MeCN), dimethyl sulfoxide (DMSO), nitromethane, propylene carbonate, or any combination thereof. In some embodiments, the polar protic solvent comprises formic acid, n-butanol, isopropyl alcohol (IPA), n-propanol, ethanol, methanol, acetic acid, or any combination thereof. In some embodiments, the organic solvent comprises N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), or any combination thereof. In some embodiments, the organic solvent comprises an alkane and / or a cycloalkane. In some embodiments, the cycloalkane comprises hexane, isoparaffin, light alkylated stone oil, cyclohexanone, or any combination thereof.

[0015] In some embodiments, the composition further comprises an inorganic solvent.

[0016] In some embodiments, the composition further comprises a polymer. In some embodiments, the polymer comprises polyvinylidene fluoride (PVDF). In some embodiments, the polyvinylidene fluoride has an average molecular weight of about 50,000 to about 1,000,000. In some embodiments, the polyvinylidene fluoride has an average molecular weight of at least about 50,000. In some embodiments, the polyvinylidene fluoride has an average molecular weight of at most about 1,000,000. In some embodiments, the polyvinylidene fluoride has an average molecular weight of about 50,000 to about 100,000, about 50,000 to about 300,000, about 50,000 to about 500,000, about 50,000 to about 700,000, about 50,000 to about 800,000, about 50,000 to about 1,000,000, about 100,000 to about 300,000, about 100,000 to about 500,000, about 100,000 to about 700,000, about 100,000 to about 800,000, about 100,000 to about 1,000,000, about 300,000 to about 500,000, about 300,000 to about 700,000, about 300,000 to about 800,000, about 300,000 to about 1,000,000, about 500,000 to about 700,000, about 500,000 to about 800,000, about 500,000 to about 1,000,000, about 700,000 to about 800,000, about 700,000 to about 1,000,000, or about 800,000 to about 1,000,000. In some embodiments, the polyvinylidene fluoride has an average molecular weight of about 50,000, about 100,000, about 300,000, about 500,000, about 700,000, about 800,000, or about 1,000,000. In some embodiments, the polyvinylidene fluoride (PVDF) has an average molecular weight of at least about 100,000. In some embodiments, the polyvinylidene fluoride (PVDF) has an average molecular weight of about 300,000 to about 700,000.

[0017] In some embodiments, the polyvinylidene fluoride (PVDF) comprises about 5% (w / w) to about 40% (w / w) of the composition. In some embodiments, the polyvinylidene fluoride (PVDF) is at least about 5% (w / w) of the composition. In some embodiments, the polyvinylidene fluoride (PVDF) is at most about 40% (w / w) of the composition. In some embodiments, the polyvinylidene fluoride (PVDF) comprises about 5% (w / w) to about 10% (w / w) of the composition, about 5% (w / w) to about 20% (w / w) of the composition, about 5% (w / w) to about 30% (w / w) of the composition, about 5% (w / w) to about 40% (w / w) of the composition, about 10% (w / w) to about 20% (w / w) of the composition, about 10% (w / w) to about 30% (w / w) of the composition, about 10% (w / w) to about 40% (w / w) of the composition, about 20% (w / w) to about 30% (w / w) of the composition, about 20% (w / w) to about 40% (w / w) of the composition, or about 30% (w / w) to about 40% (w / w) of the composition. In some embodiments, the polyvinylidene fluoride (PVDF) comprises about 5% (w / w) of the composition, about 10% (w / w) of the composition, about 20% (w / w) of the composition, about 30% (w / w) of the composition, or about 40% (w / w) of the composition. In some embodiments, the polyvinylidene fluoride (PVDF) comprises about 10% to about 30% (w / w) of the composition.

[0018] In some embodiments, the polymer comprises poly(vinylpyrrolidone) (PVP, molecular weight of 8-2000 kDa), triethylphosphate (TEP), ethylene glycol (EG), perfluorosulfonic acid, or any combination thereof. In some embodiments, the polymer comprises about 1% (w / w) to about 10% (w / w) of the composition. In some embodiments, the polymer is at least about 1% (w / w) of the composition. In some embodiments, the polymer is at most about 10% (w / w) of the composition. In some embodiments, the polymer comprises about 1% (w / w) to about 3% (w / w) of the composition, about 1% (w / w) to about 5% (w / w) of the composition, about 1% (w / w) to about 8% (w / w) of the composition, about 1% (w / w) to about 10% (w / w) of the composition, about 3% (w / w) to about 5% (w / w) of the composition, about 3% (w / w) to about 8% (w / w) of the composition, about 3% (w / w) to about 10% (w / w) of the composition, about 5% (w / w) to about 8% (w / w) of the composition, about 5% (w / w) to about 10% (w / w) of the composition, or about 8% (w / w) to about 10% (w / w) of the composition. In some embodiments, the polymer comprises about 1% (w / w) of the composition, about 3% (w / w) of the composition, about 5% (w / w) of the composition, about 8% (w / w) of the composition, or about 10% (w / w) of the composition. In some embodiments, the polymer comprises about 1% to about 8% (w / w) of the composition.

[0019] In some embodiments, the composition further comprises polyvinyl alcohol (PVA), glutaraldehyde, dichloromethane, octadecyltrichlorosilane (ODS), hydrochloric acid (HC1), or any combination thereof.

[0020] In some embodiments, the composition further comprises triethylamine (TEA), camphor sulfonic acid (CSA), dimethyl sulfoxide (DMSO), m-phenylenediamine (MPD), 2-ethyl- 1,3-hexanediol (EHD), sodium lauryl sulfate (SLES), or any combination thereof. In some embodiments, the composition comprises from about 1% (w / w) of the triethylamine to about 5% (w / w) of the triethylamine. In some embodiments, the composition comprises at least about 1% (w / w) of the triethylamine. In some embodiments, the composition comprises at most about 5% (w / w) of the triethylamine. In some embodiments, the composition comprises from about 1% (w / w) of the triethylamine to about 2% (w / w) of the triethylamine, from about 1% (w / w) of the triethylamine to about 3% (w / w) of the triethylamine, from about 1% (w / w) of the triethylamine to about 4% (w / w) of the triethylamine, from about 1% (w / w) of the triethylamine to about 5% (w / w) of the triethylamine, from about 2% (w / w) of the triethylamine to about 3% (w / w) of the triethylamine, from about 2% (w / w) of the triethylamine to about 4% (w / w) of the triethylamine, from about 2% (w / w) of the triethylamine to about 5% (w / w) of the triethylamine, from about 3% (w / w) of the triethylamine to about 4% (w / w) of the triethylamine, from about 3% (w / w) of the triethylamine to about 5% (w / w) of the triethylamine, or from about 4% (w / w) of the triethylamine to about 5% (w / w) of the triethylamine. In some embodiments, the composition comprises about 1% (w / w) of the triethylamine, about 2% (w / w) of the triethylamine, about 3% (w / w) of the triethylamine, about 4% (w / w) of the triethylamine, or about 5% (w / w) of the triethylamine.

[0021] In some embodiments, the composition comprises from about 1% (w / w) of the camphor sulfonic acid to about 7% (w / w) of the camphor sulfonic acid. In some embodiments, the composition comprises at least about 1% (w / w) of the camphor sulfonic acid. In some embodiments, the composition comprises at most about 7% (w / w) of the camphor sulfonic acid. In some embodiments, the composition comprises from about 1% (w / w) of the camphor sulfonic acid to about 3% (w / w) of the camphor sulfonic acid, from about 1% (w / w) of the camphor sulfonic acid to about 5% (w / w) of the camphor sulfonic acid, from about 1% (w / w) of the camphor sulfonic acid to about 7% (w / w) of the camphor sulfonic acid, from about 3% (w / w) of the camphor sulfonic acid to about 5% (w / w) of the camphor sulfonic acid, from about 3% (w / w) of the camphor sulfonic acid to about 7% (w / w) of the camphor sulfonic acid, or from about 5% (w / w) of the camphor sulfonic acid to about 7% (w / w) of the camphor sulfonic acid. In some embodiments, the composition comprises about 1% (w / w) of the camphor sulfonic acid, about 3% (w / w) of the camphor sulfonic acid, about 5% (w / w) of the camphor sulfonic acid, or about 7% (w / w) of the camphor sulfonic acid.

[0022] In some embodiments, the composition comprises from about 1% (w / w) of the dimethyl sulfoxide to about 3% (w / w) of the dimethyl sulfoxide. In some embodiments, the composition comprises at least about 1% (w / w) of the dimethyl sulfoxide. In some embodiments, the composition comprises at most about 3% (w / w) of the dimethyl sulfoxide. In some embodiments, the composition comprises from about 1% (w / w) of the dimethyl sulfoxide to about 1.5% (w / w) of the dimethyl sulfoxide, from about 1% (w / w) of the dimethyl sulfoxide to about 2% (w / w) of the dimethyl sulfoxide, from about 1% (w / w) of the dimethyl sulfoxide to about 2.5% (w / w) of the dimethyl sulfoxide, from about 1% (w / w) of the dimethyl sulfoxide to about 3% (w / w) of the dimethyl sulfoxide, from about 1.5% (w / w) of the dimethyl sulfoxide to about 2% (w / w) of the dimethyl sulfoxide, from about 1.5% (w / w) of the dimethyl sulfoxide to about 2.5% (w / w) of the dimethyl sulfoxide, from about 1.5% (w / w) of the dimethyl sulfoxide to about 3% (w / w) of the dimethyl sulfoxide, from about 2% (w / w) of the dimethyl sulfoxide to about 2.5% (w / w) of the dimethyl sulfoxide, from about 2% (w / w) of the dimethyl sulfoxide to about 3% (w / w) of the dimethyl sulfoxide, or from about 2.5% (w / w) of the dimethyl sulfoxide to about 3% (w / w) of the dimethyl sulfoxide. In some embodiments, the composition comprises about 1% (w / w) of the dimethyl sulfoxide, about 1.5% (w / w) of the dimethyl sulfoxide, about 2% (w / w) of the dimethyl sulfoxide, about 2.5% (w / w) of the dimethyl sulfoxide, or about 3% (w / w) of the dimethyl sulfoxide.

[0023] In some embodiments, the composition includes from about 0.2% (w / w) of the meta- phenylenediamine to about 4% (w / w) of the meta-phenylenediamine. In some embodiments, the composition includes at least about 0.2% (w / w) of the meta-phenylenediamine. In some embodiments, the composition includes at most about 4% (w / w) of the meta-phenylenediamine. In some embodiments, the composition includes from about 0.2% (w / w) of the meta-phenylenediamine to about 1% (w / w) of the meta-phenylenediamine, from about 0.2% (w / w) of the meta-phenylenediamine to about 2% (w / w) of the meta-phenylenediamine, from about 0.2% (w / w) of the meta-phenylenediamine to about 3% (w / w) of the meta-phenylenediamine, from about 0.2% (w / w) of the meta-phenylenediamine to about 4% (w / w) of the meta-phenylenediamine, from about 1% (w / w) of the meta-phenylenediamine to about 2% (w / w) of the meta-phenylenediamine, from about 1% (w / w) of the meta-phenylenediamine to about 3% (w / w) of the meta-phenylenediamine, from about 1% (w / w) of the meta-phenylenediamine to about 4% (w / w) of the meta-phenylenediamine, from about 2% (w / w) of the meta-phenylenediamine to about 3% (w / w) of the meta-phenylenediamine, from about 2% (w / w) of the meta-phenylenediamine to about 4% (w / w) of the meta-phenylenediamine, or from about 3% (w / w) of the meta-phenylenediamine to about 4% (w / w) of the meta-phenylenediamine. In some embodiments, the composition includes about 0.2% (w / w) of the meta-phenylenediamine, about 1% (w / w) of the meta-phenylenediamine, about 2% (w / w) of the meta-phenylenediamine, about 3% (w / w) of the meta-phenylenediamine, or about 4% (w / w) of the meta-phenylenediamine.

[0024] In some embodiments, the composition includes from about 0.1% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.5% (w / w) of the 2-ethyl-1,3-hexanediol. In some embodiments, the composition includes at least about 0.1% (w / w) of the 2-ethyl-1,3-hexanediol. In some embodiments, the composition includes at most about 0.5% (w / w) of the 2-ethyl-1,3-hexanediol. In some embodiments, the composition includes from about 0.1% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.2% (w / w) of the 2-ethyl-1,3-hexanediol, from about 0.1% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.3% (w / w) of the 2-ethyl-1,3-hexanediol, from about 0.1% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.4% (w / w) of the 2-ethyl-1,3-hexanediol, from about 0.1% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.5% (w / w) of the 2-ethyl-1,3-hexanediol, from about 0.2% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.3% (w / w) of the 2-ethyl-1,3-hexanediol, from about 0.2% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.4% (w / w) of the 2-ethyl-1,3-hexanediol, from about 0.2% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.5% (w / w) of the 2-ethyl-1,3-hexanediol, from about 0.3% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.4% (w / w) of the 2-ethyl-1,3-hexanediol, from about 0.3% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.5% (w / w) of the 2-ethyl-1,3-hexanediol, or from about 0.4% (w / w) of the 2-ethyl-1,3-hexanediol to about 0.5% (w / w) of the 2-ethyl-1,3-hexanediol. In some embodiments, the composition includes about 0.1% (w / w) of the 2-ethyl-1,3-hexanediol, about 0.2% (w / w) of the 2-ethyl-1,3-hexanediol, about 0.3% (w / w) of the 2-ethyl-1,3-hexanediol, about 0.4% (w / w) of the 2-ethyl-1,3-hexanediol, or about 0.5% (w / w) of the 2-ethyl-1,3-hexanediol.

[0025] In some embodiments, the composition includes from about 0.1% (w / w) of the sodium lauryl sulfate to about 0.5% (w / w) of the sodium lauryl sulfate. In some embodiments, the composition includes at least about 0.1% (w / w) of the sodium lauryl sulfate. In some embodiments, the composition includes at most about 0.5% (w / w) of the sodium lauryl sulfate. In some embodiments, the composition includes from about 0.1% (w / w) of the sodium lauryl sulfate to about 0.2% (w / w) of the sodium lauryl sulfate, from about 0.1% (w / w) of the sodium lauryl sulfate to about 0.3% (w / w) of the sodium lauryl sulfate, from about 0.1% (w / w) of the sodium lauryl sulfate to about 0.4% (w / w) of the sodium lauryl sulfate, from about 0.1% (w / w) of the sodium lauryl sulfate to about 0.5% (w / w) of the sodium lauryl sulfate, from about 0.2% (w / w) of the sodium lauryl sulfate to about 0.3% (w / w) of the sodium lauryl sulfate, from about 0.2% (w / w) of the sodium lauryl sulfate to about 0.4% (w / w) of the sodium lauryl sulfate, from about 0.2% (w / w) of the sodium lauryl sulfate to about 0.5% (w / w) of the sodium lauryl sulfate, from about 0.3% (w / w) of the sodium lauryl sulfate to about 0.4% (w / w) of the sodium lauryl sulfate, from about 0.3% (w / w) of the sodium lauryl sulfate to about 0.5% (w / w) of the sodium lauryl sulfate, or from about 0.4% (w / w) of the sodium lauryl sulfate to about 0.5% (w / w) of the sodium lauryl sulfate. In some embodiments, the composition includes about 0.1% (w / w) of the sodium lauryl sulfate, about 0.2% (w / w) of the sodium lauryl sulfate, about 0.3% (w / w) of the sodium lauryl sulfate, about 0.4% (w / w) of the sodium lauryl sulfate, or about 0.5% (w / w) of the sodium lauryl sulfate.

[0026] In some embodiments, the composition further includes 1,3,5-benzene tricarboxylic acid chloride (TMC), tributyl phosphate (TBP), or any combination thereof.

[0027] In some embodiments, the composition includes from about 0.01% (w / w) of the 1,3,5-benzene tricarboxylic acid to about 0.1% (w / w) of the 1,3,5-benzene tricarboxylic acid. In some embodiments, the composition includes at least about 0.01% (w / w) of the 1,3,5-benzene tricarboxylic acid. In some embodiments, the composition includes at most about 0.1% (w / w) of the 1,3,5-benzene tricarboxylic acid. In some embodiments, the composition includes from about 0.01% (w / w) of the 1,3,5-benzene tricarboxylic acid to about 0.05% (w / w) of the 1,3,5-benzene tricarboxylic acid, from about 0.01% (w / w) of the 1,3,5-benzene tricarboxylic acid to about 0.1% (w / w) of the 1,3,5-benzene tricarboxylic acid, or from about 0.05% (w / w) of the 1,3,5-benzene tricarboxylic acid to about 0.1% (w / w) of the 1,3,5-benzene tricarboxylic acid. In some embodiments, the composition includes about 0.01% (w / w) of the 1,3,5-benzene tricarboxylic acid, about 0.05% (w / w) of the 1,3,5-benzene tricarboxylic acid, or about 0.1% (w / w) of the 1,3,5-benzene tricarboxylic acid.

[0028] In some embodiments, the composition includes from about 0.1% (w / w) of the tributyl phosphate to about 0.5% (w / w) of the tributyl phosphate. In some embodiments, the composition includes at least about 0.1% (w / w) of the tributyl phosphate. In some embodiments, the composition includes at most about 0.5% (w / w) of the tributyl phosphate. In some embodiments, the composition includes from about 0.1% (w / w) of the tributyl phosphate to about 0.2% (w / w) of the tributyl phosphate, from about 0.1% (w / w) of the tributyl phosphate to about 0.3% (w / w) of the tributyl phosphate, from about 0.1% (w / w) of the tributyl phosphate to about 0.4% (w / w) of the tributyl phosphate, from about 0.1% (w / w) of the tributyl phosphate to about 0.5% (w / w) of the tributyl phosphate, from about 0.2% (w / w) of the tributyl phosphate to about 0.3% (w / w) of the tributyl phosphate, from about 0.2% (w / w) of the tributyl phosphate to about 0.4% (w / w) of the tributyl phosphate, from about 0.2% (w / w) of the tributyl phosphate to about 0.5% (w / w) of the tributyl phosphate, from about 0.3% (w / w) of the tributyl phosphate to about 0.4% (w / w) of the tributyl phosphate, from about 0.3% (w / w) of the tributyl phosphate to about 0.5% (w / w) of the tributyl phosphate, or from about 0.4% (w / w) of the tributyl phosphate to about 0.5% (w / w) of the tributyl phosphate. In some embodiments, the composition includes about 0.1% (w / w) of the tributyl phosphate, about 0.2% (w / w) of the tributyl phosphate, about 0.3% (w / w) of the tributyl phosphate, about 0.4% (w / w) of the tributyl phosphate, or about 0.5% (w / w) of the tributyl phosphate.

[0029] In some embodiments, the composition further comprises a carboxylic acid, oxalic acid, citric acid, phosphoric acid, benzoic acid, dihydroxybenzene, dopamine, or any combination thereof. In some embodiments, the composition further comprises polyethersulfone (PES). In some embodiments, the polyethersulfone has an average molecular weight of about 10,000 to about 80,000. In some embodiments, the polyethersulfone has an average molecular weight of at least about 10,000. In some embodiments, the polyethersulfone has an average molecular weight of at most about 80,000. In some embodiments, the polyethersulfone has an average molecular weight of about 10,000 to about 20,000, about 10,000 to about 30,000, about 10,000 to about 45,000, about 10,000 to about 55,000, about 10,000 to about 68,000, about 10,000 to about 80,000, about 20,000 to about 30,000, about 20,000 to about 45,000, about 20,000 to about 55,000, about 20,000 to about 68,000, about 20,000 to about 80,000, about 30,000 to about 45,000, about 30,000 to about 55,000, about 30,000 to about 68,000, about 30,000 to about 80,000, about 45,000 to about 55,000, about 45,000 to about 68,000, about 45,000 to about 80,000, about 55,000 to about 68,000, about 55,000 to about 80,000, or about 68,000 to about 80,000. In some embodiments, the polyethersulfone has an average molecular weight of about 10,000, about 20,000, about 30,000, about 45,000, about 55,000, about 68,000, or about 80,000.

[0030] In some embodiments, the polyether sulfone comprises about 10% (w / w) to about 40% (w / w) of the composition. In some embodiments, the polyether sulfone comprises at least about 10% (w / w) of the composition. In some embodiments, the polyether sulfone comprises at most about 40% (w / w) of the composition. In some embodiments, the polyether sulfone comprises about 10% (w / w) to about 15% (w / w), about 10% (w / w) to about 20% (w / w), about 10% (w / w) to about 25% (w / w), about 10% (w / w) to about 30% (w / w), about 10% (w / w) to about 35% (w / w), about 10% (w / w) to about 40% (w / w), about 15% (w / w) to about 20% (w / w), about 15% (w / w) to about 25% (w / w), about 15% (w / w) to about 30% (w / w), about 15% (w / w) to about 35% (w / w), about 15% (w / w) to about 40% (w / w), about 20% (w / w) to about 25% (w / w), about 20% (w / w) to about 30% (w / w), about 20% (w / w) to about 35% (w / w), about 20% (w / w) to about 40% (w / w), about 25% (w / w) to about 30% (w / w), about 25% (w / w) to about 35% (w / w), about 25% (w / w) to about 40% (w / w), about 30% (w / w) to about 35% (w / w), about 30% (w / w) to about 40% (w / w), about 35% (w / w) to about 40% (w / w) of the composition. In some embodiments, the polyether sulfone comprises about 10% (w / w), about 15% (w / w), about 20% (w / w), about 25% (w / w), about 30% (w / w), about 35% (w / w), or about 40% (w / w) of the composition.

[0031] In some embodiments, the composition further comprises a sugar. In some embodiments, the sugar comprises a monosaccharide, a disaccharide, a polysaccharide, or any combination thereof. In some embodiments, the sugar comprises glucose, fructose, sucrose, or any combination thereof.

[0032] In some embodiments, the composition comprises from about 1% (w / w) sugar to about 95% (w / w) sugar. In some embodiments, the composition comprises at least about 1% (w / w) of the sugar. In some embodiments, the composition comprises at most about 95% (w / w) of the sugar. In some embodiments, the composition comprises from about 1% (w / w) of the sugar to about 10% (w / w) of the sugar, from about 1% (w / w) of the sugar to about 20% (w / w) of the sugar, from about 1% (w / w) of the sugar to about 40% (w / w) of the sugar, from about 1% (w / w) of the sugar to about 60% (w / w) of the sugar, from about 1% (w / w) of the sugar to about 80% (w / w) of the sugar, from about 1% (w / w) of the sugar to about 95% (w / w) of the sugar, from about 10% (w / w) of the sugar to about 20% (w / w) of the sugar, from about 10% (w / w) of the sugar to about 40% (w / w) of the sugar, from about 10% (w / w) of the sugar to about 60% (w / w) of the sugar, from about 10% (w / w) of the sugar to about 80% (w / w) of the sugar, from about 10% (w / w) of the sugar to about 95% (w / w) of the sugar, from about 20% (w / w) of the sugar to about 40% (w / w) of the sugar, from about 20% (w / w) of the sugar to about 60% (w / w) of the sugar, from about 20% (w / w) of the sugar to about 80% (w / w) of the sugar, from about 20% (w / w) of the sugar to about 95% (w / w) of the sugar, from about 40% (w / w) of the sugar to about 60% (w / w) of the sugar, from about 40% (w / w) of the sugar to about 80% (w / w) of the sugar, from about 40% (w / w) of the sugar to about 95% (w / w) of the sugar, from about 60% (w / w) of the sugar to about 80% (w / w) of the sugar, from about 60% (w / w) of the sugar to about 95% (w / w) of the sugar, or from about 80% (w / w) of the sugar to about 95% (w / w) of the sugar. In some embodiments, the composition comprises about 1% (w / w) of the sugar, about 10% (w / w) of the sugar, about 20% (w / w) of the sugar, about 40% (w / w) of the sugar, about 60% (w / w) of the sugar, about 80% (w / w) of the sugar, or about 95% (w / w) of the sugar.

[0033] In another aspect, a film comprising any of the compositions disclosed herein is disclosed. In some embodiments, the film further comprises a support layer. In some embodiments, the support layer comprises a nonwoven fabric. In some embodiments, the nonwoven fabric comprises a polypropylene nonwoven fabric.

[0034] In some embodiments, the film has a water contact angle of at most about 10°, about 20°, about 30°, about 40°, about 50°, about 60°, about 70°, about 80°, or about 90°. In some embodiments, the water contact angle is about 10° to about 90°. In some embodiments, the water contact angle is about 10° to about 20°, about 10° to about 30°, about 10° to about 40°, about 10° to about 50°, about 10° to about 60°, about 10° to about 70°, about 10° to about 80°, about 10° to about 90°, about 20° to about 30°, about 20° to about 40°, about 20° to about 50°, about 20° to about 60°, about 20° to about 70°, about 20° to about 80°, about 20° to about 90°, about 30° to about 40°, about 30° to about 50°, about 30° to about 60°, about 30° to about 70°, about 30° to about 80°, about 30° to about 90°, about 40° to about 50°, about 40° to about 60°, about 40° to about 70°, about 40° to about 80°, about 40° to about 90°, about 50° to about 60°, about 50° to about 70°, about 50° to about 80°, about 50° to about 90°, about 60° to about 70°, about 60° to about 80°, about 60° to about 90°, about 70° to about 80°, about 70° to about 90°, or about 80° to about 90°. In some embodiments, the water contact angle is about 10°, about 20°, about 30°, about 40°, about 50°, about 60°, about 70°, about 80°, or about 90°. In some embodiments, the water contact angle is less than 80°. In some embodiments, the water contact angle is about 40° to about 60°.

[0035] In some embodiments, the average surface pore size of the film is about 1 nanometer to about 120 nanometers. In some embodiments, the average surface pore size of the film is at least about 1 nanometer. In some embodiments, the average surface pore size of the film is at most about 120 nanometers. In some embodiments, the average surface pore size of the film is about 1 nanometer to about 2 nanometers, about 1 nanometer to about 5 nanometers, about 1 nanometer to about 8 nanometers, about 1 nanometer to about 10 nanometers, about 1 nanometer to about 40 nanometers, about 1 nanometer to about 80 nanometers, about 1 nanometer to about 120 nanometers, about 2 nanometers to about 5 nanometers, about 2 nanometers to about 8 nanometers, about 2 nanometers to about 10 nanometers, about 2 nanometers to about 40 nanometers, about 2 nanometers to about 80 nanometers, about 2 nanometers to about 120 nanometers, about 5 nanometers to about 8 nanometers, about 5 nanometers to about 10 nanometers, about 5 nanometers to about 40 nanometers, about 5 nanometers to about 80 nanometers, about 5 nanometers to about 120 nanometers, about 8 nanometers to about 10 nanometers, about 8 nanometers to about 40 nanometers, about 8 nanometers to about 80 nanometers, about 8 nanometers to about 120 nanometers, about 10 nanometers to about 40 nanometers, about 10 nanometers to about 80 nanometers, about 10 nanometers to about 120 nanometers, about 40 nanometers to about 80 nanometers, about 40 nanometers to about 120 nanometers, or about 80 nanometers to about 120 nanometers. In some embodiments, the average surface pore size of the film is about 1 nanometer, about 2 nanometers, about 5 nanometers, about 8 nanometers, about 10 nanometers, about 40 nanometers, about 80 nanometers, or about 120 nanometers. In some embodiments, the average surface pore size of the film is at least 1 nanometer. In some embodiments, the average surface pore size is about 2 nanometers to about 8 nanometers. In some embodiments, the average surface pore size is about 10 nanometers to about 80 nanometers.

[0036] In some embodiments, the film has a porosity of about 50% to about 95%. In some embodiments, the film has a porosity of at least about 50%. In some embodiments, the film has a porosity of at most about 95%. In some embodiments, the film has a porosity of about 50% to about 60%, about 50% to about 70%, about 50% to about 80%, about 50% to about 85%, about 50% to about 90%, about 50% to about 95%, about 60% to about 70%, about 60% to about 80%, about 60% to about 85%, about 60% to about 90%, about 60% to about 95%, about 70% to about 80%, about 70% to about 85%, about 70% to about 90%, about 70% to about 95%, about 80% to about 85%, about 80% to about 90%, about 80% to about 95%, about 85% to about 90%, about 85% to about 95%, or about 90% to about 95%. In some embodiments, the film has a porosity of about 50%, about 60%, about 70%, about 80%, about 85%, about 90%, or about 95%. In some embodiments, the film has a porosity of at least 50%. In some embodiments, the porosity is about 70% to about 85%.

[0037] In some embodiments, the film has a water permeability of from about 100 LMH / bar to about 800 LMH / bar. In some embodiments, the film has a water permeability of at least about 100 LMH / bar. In some embodiments, the film has a water permeability of at most about 800 LMH / bar. In some embodiments, the film has a water permeability of from about 100 LMH / bar to about 200 LMH / bar, from about 100 LMH / bar to about 300 LMH / bar, from about 100 LMH / bar to about 400 LMH / bar, from about 100 LMH / bar to about 500 LMH / bar, from about 100 LMH / bar to about 600 LMH / bar, from about 100 LMH / bar to about 700 LMH / bar, from about 100 LMH / bar to about 800 LMH / bar, from about 200 LMH / bar to about 300 LMH / bar, from about 200 LMH / bar to about 400 LMH / bar, from about 200 LMH / bar to about 500 LMH / bar, from about 200 LMH / bar to about 600 LMH / bar, from about 200 LMH / bar to about 700 LMH / bar, from about 200 LMH / bar to about 800 LMH / bar, from about 300 LMH / bar to about 400 LMH / bar, from about 300 LMH / bar to about 500 LMH / bar, from about 300 LMH / bar to about 600 LMH / bar, from about 300 LMH / bar to about 700 LMH / bar, from about 300 LMH / bar to about 800 LMH / bar, from about 400 LMH / bar to about 500 LMH / bar, from about 400 LMH / bar to about 600 LMH / bar, from about 400 LMH / bar to about 700 LMH / bar, from about 400 LMH / bar to about 800 LMH / bar, from about 500 LMH / bar to about 600 LMH / bar, from about 500 LMH / bar to about 700 LMH / bar, from about 500 LMH / bar to about 800 LMH / bar, from about 600 LMH / bar to about 700 LMH / bar, from about 600 LMH / bar to about 800 LMH / bar, or from about 700 LMH / bar to about 800 LMH / bar. In some embodiments, the film has a water permeability of about 100 LMH / bar, about 200 LMH / bar, about 300 LMH / bar, about 400 LMH / bar, about 500 LMH / bar, about 600 LMH / bar, about 700 LMH / bar, or about 800 LMH / bar. In some embodiments, the film has a water permeability of at least 200 LMH / bar. In some embodiments, the water permeability is from about 500 LMH / bar to about 600 LMH / bar.In some embodiments, the membrane has a water permeability of at least 2 LMH / bar using a 2000 ppm sodium chloride solution at 15.5 bar.

[0038] In some embodiments, the membrane has a desalination rate of about 60% to 99%. In some embodiments, the membrane has a desalination rate of at least about 60%. In some embodiments, the membrane has a desalination rate of at most about 99%. In some embodiments, the membrane has a desalination rate of about 60% to about 80%, about 60% to about 90%, about 60% to about 95%, about 60% to about 99%, about 80% to about 90%, about 80% to about 95%, about 80% to about 99%, about 90% to about 95%, about 90% to about 99%, or about 95% to about 99%. In some embodiments, the membrane has a desalination rate of about 60%, about 80%, about 90%, about 95%, or about 99%. In some embodiments, the membrane has a desalination rate of at least 80%.

[0039] In another aspect, a water permeable device comprising any of the membranes disclosed herein is disclosed.

[0040] In another aspect, a method is disclosed that includes mixing graphite powder with an oxidizing agent to produce a composition including graphene oxide, wherein the average particle size of the graphene oxide is no more than about 1 micron and the oxygen atom percentage is at least about 30%. In some embodiments, the average particle size of the graphene oxide is about 0.001 microns to about 2 microns. In some embodiments, the average particle size of the graphene oxide is at least about 0.001 microns. In some embodiments, the average particle size of the graphene oxide is at most about 2 microns. In some embodiments, the average particle size of the graphene oxide is at most about 1.5 microns. In some embodiments, the average particle size of the graphene oxide is at most about 1 micron. In some embodiments, the average particle size of the graphene oxide is at most about 0.5 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.2 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.1 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.05 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.01 microns.In some embodiments, the average particle size of the graphene oxide is about 2 microns to about 1.5 microns, about 2 microns to about 1 micron, about 2 microns to about 0.5 microns, about 2 microns to about 0.2 microns, about 2 microns to about 0.1 microns, about 2 microns to about 0.05 microns, about 2 microns to about 0.01 microns, about 2 microns to about 0.005 microns, about 2 microns to about 0.001 microns, about 1.5 microns to about 1 micron, about 1.5 microns to about 0.5 microns, about 1.5 microns to about 0.2 microns, about 1.5 microns to about 0.1 microns, about 1.5 microns to about 0.05 microns, about 1.5 microns to about 0.01 microns, about 1.5 microns to about 0.005 microns, about 1.5 microns to about 0.001 microns, about 1 micron to about 0.5 microns, about 1 micron to about 0.2 microns, about 1 micron to about 0.1 microns, about 1 micron to about 0.05 microns, about 1 micron to about 0.01 microns, about 1 micron to about 0.005 microns, about 1 micron to about 0.001 microns, about 0.5 microns to about 0.2 microns, about 0.5 microns to about 0.1 microns, about 0.5 microns to about 0.05 microns, about 0.5 microns to about 0.01 microns, about 0.5 microns to about 0.005 microns, about 0.5 microns to about 0.001 microns, about 0.2 microns to about 0.1 microns, about 0.2 microns to about 0.05 microns, about 0.2 microns to about 0.01 microns, about 0.2 microns to about 0.005 microns, about 0.2 microns to about 0.001 microns, about 0.1 microns to about 0.05 microns, about 0.1 microns to about 0.01 microns, about 0.1 microns to about 0.005 microns, about 0.1 microns to about 0.001 microns, about 0.05 microns to about 0.01 microns, about 0.05 microns to about 0.005 microns, about 0.05 microns to about 0.001 microns, about 0.01 microns to about 0.005 microns, about 0.01 microns to about 0.001 microns, or about 0.005 microns to about 0.001 microns. In some embodiments, the average particle size of the graphene oxide is about 2 microns, about 1.5 microns, about 1 micron, about 0.5 microns, about 0.2 microns, about 0.1 microns, about 0.05 microns, about 0.01 microns, about 0.005 microns, or about 0.001 microns. In some embodiments, the composition comprising graphene oxide is any of the compositions disclosed in this application.

[0041] In some embodiments, the method further comprises milling a graphite-containing composition to produce the graphite powder, wherein the average particle size of the graphite powder is no more than about 2 microns. In some embodiments, the average particle size of the graphite powder is about 0.5 microns to about 3 microns. In some embodiments, the average particle size of the graphite powder is at least about 0.5 microns. In some embodiments, the average particle size of the graphite powder is at most about 3 microns. In some embodiments, the average particle size of the graphite powder is about 0.5 microns to about 1 micron, about 0.5 microns to about 1.5 microns, about 0.5 microns to about 2 microns, about 0.5 microns to about 2.5 microns, about 0.5 microns to about 3 microns, about 1 micron to about 1.5 microns, about 1 micron to about 2 microns, about 1 micron to about 2.5 microns, about 1 micron to about 3 microns, about 1.5 microns to about 2 microns, about 1.5 microns to about 2.5 microns, about 1.5 microns to about 3 microns, about 2 microns to about 2.5 microns, about 2 microns to about 3 microns, or about 2.5 microns to about 3 microns. In some embodiments, the average particle size of the graphite powder is about 0.5 microns, about 1 micron, about 1.5 microns, about 2 microns, about 2.5 microns, or about 3 microns.

[0042] In some embodiments, the oxidizing agent comprises oxygen (O2), ozone (O3), hydrogen peroxide (H2O2), Fenton’s reagent, fluorine (F2), chlorine (Cl2), bromine (Br2), iodine (I2), nitric acid (HNO3), sulfuric acid (H2SO4), peroxodisulfuric acid (H2S2O8), peroxymonosulfuric acid (H2SO5), chlorite, chlorate, perchlorate, hypochlorite, bleach (NaClO), chromic acid, dichromic acid, chromium trioxide, pyridinium chlorochromate (PCC), potassium permanganate, sodium perborate, nitrous oxide (N2O), nitrogen dioxide (NO2), dinitrogen tetroxide (N2O4), potassium nitrate (KNO3), sodium bismuthate, or any combination thereof. In some embodiments, the oxidizing agent comprises sulfuric acid, potassium permanganate, hydrogen peroxide, or any combination thereof.

[0043] In some embodiments, the method further comprises mixing the composition comprising graphene oxide with an organic solvent to form a mixture. In some embodiments, the organic solvent comprises a non-polar solvent, a polar aprotic solvent, a polar protic solvent, or any combination thereof. In some embodiments, the non-polar solvent comprises pentane, cyclopentane, hexane, cyclohexane, benzene, toluene, 1,4-dioxane, chloroform, diethyl ether, dichloromethane (DCM), or any combination thereof. In some embodiments, the polar aprotic solvent comprises tetrahydrofuran (THF), ethyl acetate, acetone, dimethylformamide (DMF), acetonitrile (MeCN), dimethyl sulfoxide (DMSO), nitromethane, propylene carbonate, or any combination thereof. In some embodiments, the polar protic solvent comprises formic acid, n-butanol, isopropyl alcohol (IPA), n-propanol, ethanol, methanol, acetic acid, or any combination thereof.

[0044] In some embodiments, the method further comprises isolating a solid comprising graphene oxide from the mixture. In some embodiments, the isolating comprises fractionation, centrifugation, filtration, or any combination thereof. In some embodiments, the filtration uses a pressure filter or electrodialysis.

[0045] In some embodiments, the method further comprises washing the solid comprising graphene oxide with a second organic solvent. In some embodiments, the second organic solvent comprises ethanol, methanol, or any combination thereof.

[0046] In some embodiments, the method further comprises drying the solid comprising graphene oxide.

[0047] In another aspect, a method is disclosed comprising: a) heating a sugar solution to produce a solid powder; b) mixing the solid powder with an oxidizing agent to produce a composition comprising graphene oxide, wherein the average particle size of the graphene oxide is no more than about 1 micron and the oxygen atom percentage is at least about 30%. In some embodiments, the average particle size of the graphene oxide is about 0.001 microns to about 2 microns. In some embodiments, the average particle size of the graphene oxide is at least about 0.001 microns. In some embodiments, the average particle size of the graphene oxide is at most about 2 microns. In some embodiments, the average particle size of the graphene oxide is at most about 1.5 microns. In some embodiments, the average particle size of the graphene oxide is at most about 1 micron. In some embodiments, the average particle size of the graphene oxide is at most about 0.5 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.2 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.1 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.05 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.01 microns.In some embodiments, the average particle size of the graphene oxide is about 2 microns to about 1.5 microns, about 2 microns to about 1 micron, about 2 microns to about 0.5 microns, about 2 microns to about 0.2 microns, about 2 microns to about 0.1 microns, about 2 microns to about 0.05 microns, about 2 microns to about 0.01 microns, about 2 microns to about 0.005 microns, about 2 microns to about 0.001 microns, about 1.5 microns to about 1 micron, about 1.5 microns to about 0.5 microns, about 1.5 microns to about 0.2 microns, about 1.5 microns to about 0.1 microns, about 1.5 microns to about 0.05 microns, about 1.5 microns to about 0.01 microns, about 1.5 microns to about 0.005 microns, about 1.5 microns to about 0.001 microns, about 1 micron to about 0.5 microns, about 1 micron to about 0.2 microns, about 1 micron to about 0.1 microns, about 1 micron to about 0.05 microns, about 1 micron to about 0.01 microns, about 1 micron to about 0.005 microns, about 1 micron to about 0.001 microns, about 0.5 microns to about 0.2 microns, about 0.5 microns to about 0.1 microns, about 0.5 microns to about 0.05 microns, about 0.5 microns to about 0.01 microns, about 0.5 microns to about 0.005 microns, about 0.5 microns to about 0.001 microns, about 0.2 microns to about 0.1 microns, about 0.2 microns to about 0.05 microns, about 0.2 microns to about 0.01 microns, about 0.2 microns to about 0.005 microns, about 0.2 microns to about 0.001 microns, about 0.1 microns to about 0.05 microns, about 0.1 microns to about 0.01 microns, about 0.1 microns to about 0.005 microns, about 0.1 microns to about 0.001 microns, about 0.05 microns to about 0.01 microns, about 0.05 microns to about 0.005 microns, about 0.05 microns to about 0.001 microns, about 0.01 microns to about 0.005 microns, about 0.01 microns to about 0.001 microns, or about 0.005 microns to about 0.001 microns. In some embodiments, the average particle size of the graphene oxide is about 2 microns, about 1.5 microns, about 1 micron, about 0.5 microns, about 0.2 microns, about 0.1 microns, about 0.05 microns, about 0.01 microns, about 0.005 microns, or about 0.001 microns. In some embodiments, the composition comprising graphene oxide is any of the compositions disclosed herein.

[0048] In some embodiments, the composition further comprises a sugar. In some embodiments, the sugar comprises a monosaccharide, a disaccharide, a polysaccharide, or any combination thereof. In some embodiments, the sugar comprises glucose, fructose, sucrose, or any combination thereof. In some embodiments, the composition comprises about 1% to about 60% (w / w) of the sugar.

[0049] In some embodiments, the method further comprises heating the sugar solution to between about 100 °C and about 250 °C. In some embodiments, the method further comprises heating the sugar solution to at least about 100 °C. In some embodiments, the method further comprises heating the sugar solution to at most about 250 °C. In some embodiments, the method further comprises heating the sugar solution to between about 100 °C and about 150 °C, between about 100 °C and about 180 °C, between about 100 °C and about 220 °C, between about 100 °C and about 250 °C, between about 150 °C and about 180 °C, between about 150 °C and about 220 °C, between about 150 °C and about 250 °C, between about 180 °C and about 220 °C, between about 180 °C and about 250 °C, or between about 220 °C and about 250 °C. In some embodiments, the method further comprises heating the sugar solution to about 100 °C, about 150 °C, about 180 °C, about 220 °C, or about 250 °C. In some embodiments, the method further comprises heating the sugar solution to at least 100 °C. In some embodiments, the method further comprises heating the sugar solution to between 180 °C and 220 °C.

[0050] In some embodiments, the method further comprises heating the sugar solution at a pressure of between about 2 atm and about 20 atm. In some embodiments, the method further comprises heating the sugar solution at a pressure of at least about 2 atm. In some embodiments, the method further comprises heating the sugar solution at a pressure of at most about 20 atm. In some embodiments, the method further comprises heating the sugar solution to between about 2 atm and about 6 atm, between about 2 atm and about 10 atm, between about 2 atm and about 12 atm, between about 2 atm and about 15 atm, between about 2 atm and about 20 atm, between about 6 atm and about 10 atm, between about 6 atm and about 12 atm, between about 6 atm and about 15 atm, between about 6 atm and about 20 atm, between about 10 atm and about 12 atm, between about 10 atm and about 15 atm, between about 10 atm and about 20 atm, between about 12 atm and about 15 atm, between about 12 atm and about 20 atm, or between about 15 atm and about 20 atm. In some embodiments, the method further comprises heating the sugar solution at about 2 atm, about 6 atm, about 10 atm, about 12 atm, about 15 atm, or about 20 atm. In some embodiments, the method further comprises heating the sugar solution at a pressure greater than 2 atm. In some embodiments, the method further comprises heating the sugar solution at a pressure between 12 atm and 20 atm.

[0051] In some embodiments, the oxidizing agent comprises oxygen (O2), ozone (O3), hydrogen peroxide (H2O2), Fenton's reagent, fluorine (F2), chlorine (Cl2), bromine (Br2), iodine (I2), nitric acid (HNO3), sulfuric acid (H2SO4), peroxodisulfuric acid (H2S2O8), peroxymonosulfuric acid (H2SO5), chlorite, chlorate, perchlorate, hypochlorite, bleach (NaClO), chromic acid, dichromic acid, chromium trioxide, pyridinium chlorochromate (PCC), potassium permanganate, sodium perborate, nitrous oxide (N2O), nitrogen dioxide (NO2), dinitrogen tetroxide (N2O4), potassium nitrate (KNO3), sodium bismuthate, or any combination thereof. In some embodiments, the oxidizing agent comprises sulfuric acid, potassium permanganate, hydrogen peroxide, or any combination thereof.

[0052] In some embodiments, the method further comprises separating a solid comprising graphene oxide from the oxidizing agent. In some embodiments, the separating comprises fractional distillation, centrifugation, filtration, or any combination thereof. In some embodiments, the filtration uses a pressure filter or electrodialysis.

[0053] In some embodiments, the method further comprises washing the solid comprising graphene oxide with a second organic solvent. In some embodiments, the second organic solvent comprises ethanol, methanol, or any combination thereof.

[0054] In some embodiments, the method further comprises drying the solid comprising graphene oxide.

[0055] In another aspect, a method is disclosed comprising: a) mixing a sugar component with an acid component; b) heating the sugar component to produce a composition comprising graphene oxide, wherein the average particle size of the graphene oxide is no more than about 1 micron and the oxygen atom percentage is at least about 30%. In some embodiments, the average particle size of the graphene oxide is from about 0.001 microns to about 2 microns. In some embodiments, the average particle size of the graphene oxide is at least about 0.001 microns. In some embodiments, the average particle size of the graphene oxide is at most about 2 microns. In some embodiments, the average particle size of the graphene oxide is at most about 1.5 microns. In some embodiments, the average particle size of the graphene oxide is at most about 1 micron. In some embodiments, the average particle size of the graphene oxide is at most about 0.5 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.2 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.1 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.05 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.01 microns.In some embodiments, the average particle size of the graphene oxide is about 2 microns to about 1.5 microns, about 2 microns to about 1 micron, about 2 microns to about 0.5 microns, about 2 microns to about 0.2 microns, about 2 microns to about 0.1 microns, about 2 microns to about 0.05 microns, about 2 microns to about 0.01 microns, about 2 microns to about 0.005 microns, about 2 microns to about 0.001 microns, about 1.5 microns to about 1 micron, about 1.5 microns to about 0.5 microns, about 1.5 microns to about 0.2 microns, about 1.5 microns to about 0.1 microns, about 1.5 microns to about 0.05 microns, about 1.5 microns to about 0.01 microns, about 1.5 microns to about 0.005 microns, about 1.5 microns to about 0.001 microns, about 1 micron to about 0.5 microns, about 1 micron to about 0.2 microns, about 1 micron to about 0.1 microns, about 1 micron to about 0.05 microns, about 1 micron to about 0.01 microns, about 1 micron to about 0.005 microns, about 1 micron to about 0.001 microns, about 0.5 microns to about 0.2 microns, about 0.5 microns to about 0.1 microns, about 0.5 microns to about 0.05 microns, about 0.5 microns to about 0.01 microns, about 0.5 microns to about 0.005 microns, about 0.5 microns to about 0.001 microns, about 0.2 microns to about 0.1 microns, about 0.2 microns to about 0.05 microns, about 0.2 microns to about 0.01 microns, about 0.2 microns to about 0.005 microns, about 0.2 microns to about 0.001 microns, about 0.1 microns to about 0.05 microns, about 0.1 microns to about 0.01 microns, about 0.1 microns to about 0.005 microns, about 0.1 microns to about 0.001 microns, about 0.05 microns to about 0.01 microns, about 0.05 microns to about 0.005 microns, about 0.05 microns to about 0.001 microns, about 0.01 microns to about 0.005 microns, about 0.01 microns to about 0.001 microns, or about 0.005 microns to about 0.001 microns. In some embodiments, the average particle size of the graphene oxide is about 2 microns, about 1.5 microns, about 1 micron, about 0.5 microns, about 0.2 microns, about 0.1 microns, about 0.05 microns, about 0.01 microns, about 0.005 microns, or about 0.001 microns. In some embodiments, the composition comprising graphene oxide is any of the compositions disclosed herein.

[0056] In some embodiments, the acidic component comprises a carboxylic acid, oxalic acid, citric acid, phosphoric acid, benzoic acid, dihydroxybenzene, dopamine, or any combination thereof.

[0057] In some embodiments, the sugar comprises about 1% to about 60% (w / w) of the composition comprising graphene oxide. In some embodiments, the sugar comprises a monosaccharide, a disaccharide, a polysaccharide, or any combination thereof. In some embodiments, the sugar comprises glucose, fructose, sucrose, or any combination thereof.

[0058] In some embodiments, the method further comprises heating the sugar solution to between about 100 °C and about 250 °C. In some embodiments, the method further comprises heating the sugar solution to at least about 100 °C. In some embodiments, the method further comprises heating the sugar solution to at most about 250 °C. In some embodiments, the method further comprises heating the sugar solution to between about 100 °C and about 150 °C, between about 100 °C and about 180 °C, between about 100 °C and about 220 °C, between about 100 °C and about 250 °C, between about 150 °C and about 180 °C, between about 150 °C and about 220 °C, between about 150 °C and about 250 °C, between about 180 °C and about 220 °C, between about 180 °C and about 250 °C, or between about 220 °C and about 250 °C. In some embodiments, the method further comprises heating the sugar solution to about 100 °C, about 150 °C, about 180 °C, about 220 °C, or about 250 °C. In some embodiments, the method further comprises heating the sugar solution to at least 100 °C. In some embodiments, the method further comprises heating the sugar solution to between 180 °C and 220 °C.

[0059] In some embodiments, the method further comprises heating the sugar solution to between about 2 atm and about 20 atm. In some embodiments, the method further comprises heating the sugar solution at a pressure of at least about 2 atm. In some embodiments, the method further comprises heating the sugar solution at a pressure of at most about 20 atm. In some embodiments, the method further comprises heating the sugar solution to between about 2 atm and about 6 atm, between about 2 atm and about 10 atm, between about 2 atm and about 12 atm, between about 2 atm and about 15 atm, between about 2 atm and about 20 atm, between about 6 atm and about 10 atm, between about 6 atm and about 12 atm, between about 6 atm and about 15 atm, between about 6 atm and about 20 atm, between about 10 atm and about 12 atm, between about 10 atm and about 15 atm, between about 10 atm and about 20 atm, between about 12 atm and about 15 atm, between about 12 atm and about 20 atm, or between about 15 atm and about 20 atm. In some embodiments, the method further comprises heating the sugar solution at about 2 atm, about 6 atm, about 10 atm, about 12 atm, about 15 atm, or about 20 atm. In some embodiments, the method further comprises heating the sugar solution at a pressure greater than 2 atm. In some embodiments, the method further comprises heating the sugar solution at a pressure between 12 atm and 20 atm.

[0060] In some embodiments, the method further comprises separating the solid comprising graphene oxide from the acidic component. In some embodiments, the separating comprises fractionation, centrifugation, filtration, or any combination thereof. In some embodiments, the filtration uses a pressure filter or electrodialysis.

[0061] In some embodiments, the method further comprises washing the solid comprising graphene oxide with a second organic solvent. In some embodiments, the second organic solvent comprises ethanol, methanol, or any combination thereof.

[0062] In some embodiments, the method further comprises drying the solid comprising graphene oxide.

[0063] In another aspect, a method is disclosed comprising: a) mixing a graphite powder with a first oxidizing agent to produce a first composition comprising graphene oxide; b) mixing the first composition comprising graphene oxide with a second oxidizing agent to produce a second composition comprising graphene oxide, wherein the average particle size of the graphene oxide is no more than about 1 micron and the oxygen atom percentage is at least about 30%. In some embodiments, the average particle size of the graphene oxide is from about 0.001 microns to about 2 microns. In some embodiments, the average particle size of the graphene oxide is at least about 0.001 microns. In some embodiments, the average particle size of the graphene oxide is at most about 2 microns. In some embodiments, the average particle size of the graphene oxide is at most about 1.5 microns. In some embodiments, the average particle size of the graphene oxide is at most about 1 micron. In some embodiments, the average particle size of the graphene oxide is at most about 0.5 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.2 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.1 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.05 microns. In some embodiments, the average particle size of the graphene oxide is at most about 0.01 microns.In some embodiments, the average particle size of the graphene oxide is about 2 microns to about 1.5 microns, about 2 microns to about 1 micron, about 2 microns to about 0.5 microns, about 2 microns to about 0.2 microns, about 2 microns to about 0.1 microns, about 2 microns to about 0.05 microns, about 2 microns to about 0.01 microns, about 2 microns to about 0.005 microns, about 2 microns to about 0.001 microns, about 1.5 microns to about 1 micron, about 1.5 microns to about 0.5 microns, about 1.5 microns to about 0.2 microns, about 1.5 microns to about 0.1 microns, about 1.5 microns to about 0.05 microns, about 1.5 microns to about 0.01 microns, about 1.5 microns to about 0.005 microns, about 1.5 microns to about 0.001 microns, about 1 micron to about 0.5 microns, about 1 micron to about 0.2 microns, about 1 micron to about 0.1 microns, about 1 micron to about 0.05 microns, about 1 micron to about 0.01 microns, about 1 micron to about 0.005 microns, about 1 micron to about 0.001 microns, about 0.5 microns to about 0.2 microns, about 0.5 microns to about 0.1 microns, about 0.5 microns to about 0.05 microns, about 0.5 microns to about 0.01 microns, about 0.5 microns to about 0.005 microns, about 0.5 microns to about 0.001 microns, about 0.2 microns to about 0.1 microns, about 0.2 microns to about 0.05 microns, about 0.2 microns to about 0.01 microns, about 0.2 microns to about 0.005 microns, about 0.2 microns to about 0.001 microns, about 0.1 microns to about 0.05 microns, about 0.1 microns to about 0.01 microns, about 0.1 microns to about 0.005 microns, about 0.1 microns to about 0.001 microns, about 0.05 microns to about 0.01 microns, about 0.05 microns to about 0.005 microns, about 0.05 microns to about 0.001 microns, about 0.01 microns to about 0.005 microns, about 0.01 microns to about 0.001 microns, or about 0.005 microns to about 0.001 microns. In some embodiments, the average particle size of the graphene oxide is about 2 microns, about 1.5 microns, about 1 micron, about 0.5 microns, about 0.2 microns, about 0.1 microns, about 0.05 microns, about 0.01 microns, about 0.005 microns, or about 0.001 microns. In some embodiments, the composition comprising graphene oxide is any of the compositions disclosed herein.

[0064] In some embodiments, the first oxidizing agent comprises oxygen (O2), ozone (O3), hydrogen peroxide (H2O2), Fenton’s reagent, fluorine (F2), chlorine (Cl2), bromine (Br2), iodine (I2), nitric acid (HN03), sulfuric acid (H2S04), peroxodisulfuric acid (H2S208), peroxymonosulfuric acid (H2S05), chlorite, chlorate, perchlorate, hypochlorite, bleach (NaCIO), chromic acid, dichromic acid, chromium trioxide, pyridinium chlorochromate (PCC), potassium permanganate, sodium perborate, nitrous oxide (N20), nitrogen dioxide (NO2), dinitrogen tetroxide (N204), potassium nitrate (KNO3), sodium bismuthate, or any combination thereof. In some embodiments, the first oxidizing agent comprises sulfuric acid, potassium permanganate, hydrogen peroxide, or any combination thereof.

[0065] In some embodiments, the method further comprises separating a first composition comprising graphene oxide from the first oxidizing agent. In some embodiments, the separation comprises fractional distillation, centrifugation, filtration, or any combination thereof. In some embodiments, the filtration uses a pressure filter or electrodialysis. In some embodiments, the second oxidizing agent comprises sulfuric acid, potassium permanganate, hydrogen peroxide, or any combination thereof.

[0066] In some embodiments, the method further comprises separating the second composition comprising graphene oxide from the second oxidizing agent.

[0067] In some embodiments, the method further comprises washing the second composition comprising graphene oxide with a second organic solvent. In some embodiments, the second organic solvent comprises ethanol, methanol, or any combination thereof.

[0068] In some embodiments, the method further comprises drying the second composition comprising graphene oxide.

[0069] In another aspect, a method of making a film is disclosed, comprising: mixing the composition of any of the preceding embodiments with an organic solvent. In some embodiments, the organic solvent comprises N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), or any combination thereof. In some embodiments, the organic solvent comprises an alkane and / or a cyclic ketone. In some embodiments, the cyclic ketone comprises hexane, isoparaffin, light alkylated naphtha, cyclohexanone, or any combination thereof.

[0070] In some embodiments, the method further comprises mixing the composition with an inorganic solvent. In some embodiments, the method further comprises dispersing the composition in the organic solvent using a high pressure homogenizer to produce an organic solution comprising graphene oxide.

[0071] In some embodiments, the method further comprises dispersing the composition in the inorganic solvent using a high pressure homogenizer to produce an inorganic solution comprising graphene oxide. In some embodiments, the dispersing is performed at about 5000 psi to about 30000 psi. In some embodiments, the dispersing is performed at a pressure of at least about 5000 psi. In some embodiments, the dispersing is performed at a pressure of at most about 30000 psi. In some embodiments, the dispersing is performed at about 5000 psi to about 10000 psi, about 5000 psi to about 15000 psi, about 5000 psi to about 20000 psi, about 5000 psi to about 25000 psi, about 5000 psi to about 30000 psi, about 5000 psi, 10000 psi to about 15000 psi, about 10000 psi to about 20000 psi, about 10000 psi to about 25000 psi, about 10000 psi to about 30000 psi, about 15000 psi to about 20000 psi, about 15000 psi to about 25000 psi, about 15000 psi to about 30000 psi, about 20000 psi to about 25000 psi, about 20000 psi to about 30000 psi, or about 25000 psi to about 30000 psi. In some embodiments, the dispersing is performed at about 5000 psi, about 10000 psi, about 15000 psi, about 20000 psi, about 25000 psi, or about 30000 psi. In some embodiments, the dispersing is performed at a pressure greater than 10000 psi. In some embodiments, the dispersing is performed at 15000-20000 psi.

[0072] In some embodiments, the dispersing is performed about 2 times to about 5 times. In some embodiments, the dispersing is performed at least about 2 times. In some embodiments, the dispersing is performed at most about 5 times. In some embodiments, the dispersing is performed about 2 times to about 3 times, about 2 times to about 4 times, about 2 times to about 5 times, about 3 times to about 4 times, about 3 times to about 5 times, or about 4 times to about 5 times. In some embodiments, the dispersing is performed about 2 times, about 3 times, about 4 times, or about 5 times.

[0073] In some embodiments, the method further comprises mixing the organic solution comprising graphene oxide with a polymer to form a polymer solution. In some embodiments, the polymer comprises polyvinylidene fluoride (PVDF). In some embodiments, the polyvinylidene fluoride has an average molecular weight of about 50,000 to about 1,000,000. In some embodiments, the polyvinylidene fluoride has an average molecular weight of at least about 50,000. In some embodiments, the polyvinylidene fluoride has an average molecular weight of at most about 1,000,000. In some embodiments, the polyvinylidene fluoride has an average molecular weight of about 50,000 to about 100,000, about 50,000 to about 300,000, about 50,000 to about 500,000, about 50,000 to about 700,000, about 50,000 to about 800,000, about 50,000 to about 1,000,000, about 100,000 to about 300,000, about 100,000 to about 500,000, about 100,000 to about 700,000, about 100,000 to about 800,000, about 100,000 to about 1,000,000, about 300,000 to about 500,000, about 300,000 to about 700,000, about 300,000 to about 800,000, about 300,000 to about 1,000,000, about 500,000 to about 700,000, about 500,000 to about 800,000, about 500,000 to about 1,000,000, about 700,000 to about 800,000, about 700,000 to about 1,000,000, or about 800,000 to about 1,000,000. In some embodiments, the polyvinylidene fluoride has an average molecular weight of about 50,000, about 100,000, about 300,000, about 500,000, about 700,000, about 800,000, or about 1,000,000. In some embodiments, the polyvinylidene fluoride (PVDF) has an average molecular weight of at least about 100,000. In some embodiments, the average molecular weight is about 300,000 to about 700,000.

[0074] In some embodiments, the polyvinylidene fluoride (PVDF) is about 5% (w / w) to about 40% (w / w) of the composition. In some embodiments, the polyvinylidene fluoride (PVDF) is at least about 5% (w / w) of the composition. In some embodiments, the polyvinylidene fluoride (PVDF) is at most about 40% (w / w) of the composition. In some embodiments, the polyvinylidene fluoride (PVDF) is about 5% (w / w) to about 10% (w / w) of the composition, about 5% (w / w) to about 20% (w / w) of the composition, about 5% (w / w) to about 30% (w / w) of the composition, about 5% (w / w) to about 40% (w / w) of the composition, about 10% (w / w) to about 20% (w / w) of the composition, about 10% (w / w) to about 30% (w / w) of the composition, about 10% (w / w) to about 40% (w / w) of the composition, about 20% (w / w) to about 30% (w / w) of the composition, about 20% (w / w) to about 40% (w / w) of the composition, or about 30% (w / w) to about 40% (w / w) of the composition. In some embodiments, the polyvinylidene fluoride (PVDF) is about 5% (w / w), about 10% (w / w), about 20% (w / w), about 30% (w / w), or about 40% (w / w) of the composition. In some embodiments, the polyvinylidene fluoride (PVDF) is about 10% to about 30% (w / w) of the composition.

[0075] In some embodiments, the polymer comprises polyether sulfone (PES). In some embodiments, the average molecular weight of the polyether sulfone is from about 10,000 to about 80,000. In some embodiments, the average molecular weight of the polyether sulfone is at least about 10,000. In some embodiments, the average molecular weight of the polyether sulfone is at most about 80,000. In some embodiments, the average molecular weight of the polyether sulfone is from about 10,000 to about 20,000, from about 10,000 to about 30,000, from about 10,000 to about 45,000, from about 10,000 to about 55,000, from about 10,000 to about 68,000, from about 10,000 to about 80,000, from about 20,000 to about 30,000, from about 20,000 to about 45,000, from about 20,000 to about 55,000, from about 20,000 to about 68,000, from about 20,000 to about 80,000, from about 30,000 to about 45,000, from about 30,000 to about 55,000, from about 30,000 to about 68,000, from about 30,000 to about 80,000, from about 45,000 to about 55,000, from about 45,000 to about 68,000, from about 45,000 to about 80,000, from about 55,000 to about 68,000, from about 55,000 to about 80,000, or from about 68,000 to about 80,000. In some embodiments, the average molecular weight of the polyether sulfone is about 10,000, about 20,000, about 30,000, about 45,000, about 55,000, about 68,000, or about 80,000.

[0076] In some embodiments, the polyether sulfone is about 10% (w / w) to about 40% (w / w) of the composition. In some embodiments, the polyether sulfone is at least about 10% (w / w) of the composition. In some embodiments, the polyether sulfone is at most about 40% (w / w) of the composition. In some embodiments, the polyether sulfone is about 10% (w / w) of the composition to about 15% (w / w) of the composition, about 10% (w / w) of the composition to about 20% (w / w) of the composition, about 10% (w / w) of the composition to about 25% (w / w) of the composition, about 10% (w / w) of the composition to about 30% (w / w) of the composition, about 10% (w / w) of the composition to about 35% (w / w) of the composition, about 10% (w / w) of the composition to about 40% (w / w) of the composition, about 15% (w / w) of the composition to about 20% (w / w) of the composition, about 15% (w / w) of the composition to about 25% (w / w) of the composition, about 15% (w / w) of the composition to about 30% (w / w) of the composition, about 15% (w / w) of the composition to about 35% (w / w) of the composition, about 15% (w / w) of the composition to about 40% (w / w) of the composition, about 20% (w / w) of the composition to about 25% (w / w) of the composition, about 20% (w / w) of the composition to about 30% (w / w) of the composition, about 20% (w / w) of the composition to about 35% (w / w) of the composition, about 20% (w / w) of the composition to about 40% (w / w) of the composition, about 25% (w / w) of the composition to about 30% (w / w) of the composition, about 25% (w / w) of the composition to about 35% (w / w) of the composition, about 25% (w / w) of the composition to about 40% (w / w) of the composition, about 30% (w / w) of the composition to about 35% (w / w) of the composition, about 30% (w / w) of the composition to about 40% (w / w) of the composition, or about 35% (w / w) of the composition to about 35% (w / w) of the composition. In some embodiments, the polyether sulfone is about 10% (w / w) of the composition, about 15% (w / w) of the composition, about 20% (w / w) of the composition, about 25% (w / w) of the composition, about 30% (w / w) of the composition, about 35% (w / w) of the composition, or about 40% (w / w) of the composition.

[0077] In some embodiments, the polymer comprises poly(vinylpyrrolidone) (PVP molecular weight = 8-2000 kDa), triethylphosphate (TEP), ethylene glycol (EG), perfluorosulfonic acid, or any combination thereof. In some embodiments, the polymer comprises about 1% (w / w) to about 10% (w / w) of the composition. In some embodiments, the polymer comprises at least about 1% (w / w) of the composition. In some embodiments, the polymer comprises at most about 10% (w / w) of the composition. In some embodiments, the polymer comprises about 1% (w / w) of the composition to about 3% (w / w) of the composition, about 1% (w / w) of the composition to about 5% (w / w) of the composition, about 1% (w / w) of the composition to about 8% (w / w) of the composition, about 1% (w / w) of the composition to about 10% (w / w) of the composition, about 3% (w / w) of the composition to about 5% (w / w) of the composition, about 3% (w / w) of the composition to about 8% (w / w) of the composition, about 3% (w / w) of the composition to about 10% (w / w) of the composition, about 5% (w / w) of the composition to about 8% (w / w) of the composition, about 5% (w / w) of the composition to about 10% (w / w) of the composition, or about 8% (w / w) of the composition to about 10% (w / w) of the composition. In some embodiments, the polymer comprises about 1% (w / w) of the composition, about 3% (w / w) of the composition, about 5% (w / w) of the composition, about 8% (w / w) of the composition, or about 10% (w / w) of the composition. In some embodiments, the polymer comprises about 1% to about 8% (w / w) of the composition.

[0078] In some embodiments, the method further comprises heating the polymer solution to 60-70 °C. In some embodiments, the method further comprises mixing the polymer solution with water using a rotating device. In some embodiments, the method further comprises mixing the polymer solution with a solution comprising polyvinyl alcohol (PVA), glutaraldehyde, dichloromethane, octadecyltrichlorosilane (ODS), hydrochloric acid (HC1), or any combination thereof. In some embodiments, the method further comprises mixing the polymer solution with a glycerol solution to form a hollow fiber membrane.

[0079] In some embodiments, the polymer comprises a polyfulfone. In some embodiments, the polyfulfone has an average molecular weight of about 40,000 to about 100,000. In some embodiments, the polyfulfone has an average molecular weight of at least about 40,000. In some embodiments, the polyfulfone has an average molecular weight of at most about 100,000. In some embodiments, the polyfulfone has an average molecular weight of about 40,000 to about 50,000, about 40,000 to about 60,000, about 40,000 to about 67,000, about 40,000 to about 75,000, about 40,000 to about 81,000, about 40,000 to about 90,000, about 40,000 to about 100,000, about 50,000 to about 60,000, about 50,000 to about 67,000, about 50,000 to about 75,000, about 50,000 to about 81,000, about 50,000 to about 90,000, about 50,000 to about 100,000, about 60,000 to about 67,000, about 60,000 to about 75,000, about 60,000 to about 81,000, about 60,000 to about 90,000, about 60,000 to about 100,000, about 67,000 to about 75,000, about 67,000 to about 81,000, about 67,000 to about 90,000, about 67,000 to about 100,000, about 75,000 to about 81,000, about 75,000 to about 90,000, about 75,000 to about 100,000, about 81,000 to about 90,000, about 81,000 to about 100,000, or about 90,000 to about 100,000. In some embodiments, the polyfulfone has an average molecular weight of about 40,000, about 50,000, about 60,000, about 67,000, about 75,000, about 81,000, about 90,000, or about 100,000.

[0080] In some embodiments, the polysulfone is about 10% (w / w) to about 40% (w / w) of the composition. In some embodiments, the polysulfone is at least about 10% (w / w) of the composition. In some embodiments, the polysulfone is at most about 40% (w / w) of the composition. In some embodiments, the polysulfone is about 10% (w / w) of the composition to about 20% (w / w) of the composition, about 10% (w / w) of the composition to about 30% (w / w) of the composition, about 10% (w / w) of the composition to about 40% (w / w) of the composition, about 20% (w / w) of the composition to about 30% (w / w) of the composition, about 20% (w / w) of the composition to about 40% (w / w) of the composition, or about 30% (w / w) of the composition to about 40% (w / w) of the composition. In some embodiments, the polysulfone is about 10% (w / w) of the composition, about 20% (w / w) of the composition, about 30% (w / w) of the composition, or about 40% (w / w) of the composition.

[0081] In some embodiments, the polymer comprises polysulfone (PSU), polyetherimide (PEI), polyethersulfone (PES), or any combination thereof.

[0082] In some embodiments, the method further comprises coating a support layer with the polymer solution. In some embodiments, the method further comprises the inorganic solution comprising graphene oxide with triethylamine (TEA), camphorsulfonic acid (CSA), dimethyl sulfoxide (DMSO), m-phenylenediamine (MPD), 2-ethyl-1,3-hexanediol (EHD), sodium lauryl sulfate (SLES), or any combination thereof.

[0083] In some embodiments, the triethylamine (TEA) is about 1% to about 4% (w / w) of the composition. In some embodiments, the camphorsulfonic acid (CSA) is about 1% to about 5% (w / w) of the composition. In some embodiments, the dimethyl sulfoxide (DMSO) is about 1% to about 2% (w / w) of the composition. In some embodiments, the m-phenylenediamine (MPD) is about 0.2% to about 3% (w / w) of the composition. In some embodiments, the 2-ethyl-1,3-hexanediol (EHD) is about 0.1% to about 0.4% (w / w) of the composition. In some embodiments, the sodium lauryl sulfate (SLES) is about 0.1% to about 0.4% (w / w) of the composition.

[0084] In some embodiments, the method further comprises mixing the organic solution comprising graphene oxide with 1,3,5-benzene tricarboxylic acid chloride (TMC), tributyl phosphate (TBP), or any combination thereof. In some embodiments, the 1,3,5-benzene tricarboxylic acid chloride (TMC) is about 0.01% to about 0.1% (w / w) of the composition. In some embodiments, the tributyl phosphate (TBP) is about 0.1% to about 0.5% (w / w) of the composition.

[0085] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0086] The application can be better understood from the following detailed description taken in conjunction with the accompanying drawings, from which:

[0087] Figure 1A A transmission electron microscope image of graphene oxide prepared using sugar and acid according to Example 3 is shown;

[0088] Figure 1B An atomic force microscope image of graphene oxide prepared using sugar and acid according to Example 3 at a first magnification is shown;

[0089] Figure 1C An atomic force microscope image of graphene oxide prepared using sugar and acid according to Example 3 at a second magnification is shown;

[0090] Figure 2A A freshly prepared graphene oxide particle observed using an electron microscope is shown;

[0091] Figure 2B A graphene oxide particle observed under an electron microscope after using about 180 liters of oxidizing solution is shown;

[0092] Figure 3 A composition of graphene oxide characterized using UV-Vis spectroscopy is shown;

[0093] Figure 4 A flow diagram of a method of preparing a graphene oxide composite ultrafiltration membrane is shown;

[0094] Figure 5A A scanning electron microscope image of a cross-section of a graphene oxide-PVDF composite ultrafiltration hollow fiber membrane prepared according to Example 6 at a first magnification is shown;

[0095] Figure 5BA scanning electron microscope image of the surface of a graphene oxide-PVDF composite ultrafiltration hollow fiber membrane prepared according to Example 6 at a first magnification is shown;

[0096] Figure 5C A scanning electron microscope image of the surface of a graphene oxide-PVDF composite ultrafiltration hollow fiber membrane prepared according to Example 6 at a first magnification is shown;

[0097] Figure 5D A scanning electron microscope image of the surface of a graphene oxide-PVDF composite ultrafiltration hollow fiber membrane prepared according to Example 6 at a second magnification is shown;

[0098] Figure 6 A flow chart of a method of preparing a second graphene oxide composite ultrafiltration membrane is shown;

[0099] Figure 7A A scanning electron microscope image of the surface of a graphene oxide-PSF composite ultrafiltration membrane prepared according to Example 7 at a first magnification is shown;

[0100] Figure 7B A scanning electron microscope image of the surface of a graphene oxide-PSF composite ultrafiltration membrane prepared according to Example 7 at a second magnification is shown;

[0101] Figure 8 A flow chart of a method of preparing a graphene oxide composite nanofiltration membrane is shown;

[0102] Figure 9 A flow chart of a method of preparing a second graphene oxide composite nanofiltration membrane is shown;

[0103] Figure 10 A flow chart of a method of preparing a graphene oxide composite polyamide selective layer is shown;

[0104] Figure 11A A scanning electron microscope image of the surface of a graphene oxide composite reverse osmosis membrane prepared according to Example 10 at a first magnification is shown;

[0105] Figure 11B A scanning electron microscope image of the surface of a graphene oxide composite reverse osmosis membrane prepared according to Example 10 at a second magnification is shown; and

[0106] Figure 11C A scanning electron microscope image of the surface of a graphene oxide composite reverse osmosis membrane prepared according to Example 10 at a third magnification is shown. DETAILED DESCRIPTION

[0107] Disclosed are compositions, membranes, devices, and methods of making graphene oxide-containing water filtration systems.

[0108] The term "about" and its grammatically equivalent synonyms when used in reference to a value disclosed herein can include a range of values plus or minus 10% of the value, e.g., plus or minus 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1% of the value. For example, the quantity "about 10" includes quantities from 9 to 11.

[0109] Unless the context clearly indicates otherwise, as used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, including combinations thereof, unless the context clearly indicates otherwise. Thus, the listed numerical values in the present disclosure are approximations that can vary depending on the desired properties to be obtained by the embodiments.

[0110] Unless otherwise indicated, the open terms such as "comprising," "comprises" "including," "includes," "having," "has," and similar terms are to be construed to be inclusive or open-ended terminology indicating that additional non-specified elements can be present.

[0111] The term "atomic percentage" as used in the present disclosure can mean the percentage of one atom with respect to the total number of atoms. The atomic percentage can be calculated as: Atomic percentage = N i / N tot x 100%.

[0112] Embodiments

[0113] The following examples can more specifically illustrate the general nature of the present disclosure. These examples of the present disclosure are exemplary and not limiting.

[0114] Example 1 - Synthesis of graphene oxide using graphite powder

[0115] In this example, graphite powder is subjected to mechanical pulverization and / or grinding treatment to obtain ultra-fine graphite powder having an average particle size of not more than 2 microns. One kilogram of ultra-fine graphite powder and 5-10 kilograms of potassium permanganate powder are added to a reactor, the lining of which is coated with polytetrafluoroethylene or glass coating, and is continuously stirred uniformly with a stirrer, cooled and maintained at a constant temperature of less than 10°C. Concentrated sulfuric acid (e.g., concentration greater than 94%) is added slowly in a total volume of 40-100 liters, and the mixture is stirred thoroughly for 15 minutes to 1 hour.

[0116] The reactor is heated to 40-50°C and maintained at this temperature for 2-24 hours, then the reactor is cooled and maintained at a constant temperature of less than 10°C, and 40-200 kilograms of ice made of deionized water is added to the reactor, and stirring is continued until all the ice is melted and the solution temperature no longer fluctuates. The volume ratio of deionized water to sulfuric acid can be 1:1 to 1:2.

[0117] The reaction is continuously stirred and 2-50 liters of hydrogen peroxide is slowly added until the solution turns yellow and no more gas is produced. The amount of hydrogen peroxide added can be proportional to the amount of potassium permanganate added.

[0118] The reactor is charged with 80-300 liters of an organic solution, which can be a mixture of acetone, dichloromethane, hexane, carboxylic acid ester (e.g., ethyl acetate), and straight-chain primary alcohol (e.g., butanol). The solution is continuously stirred and heated, and kept at a constant temperature of 40-60°C, stirred for another 0.5-4 hours, and finally the device is cooled to room temperature and the stirring is stopped.

[0119] The solution in the reactor is layered. The upper layer is a brown organic solution containing the graphene oxide produced by the reaction. The lower layer is a transparent colorless liquid containing sulfuric acid and a small amount of hydrogen peroxide, with some crystallized solids.

[0120] The transparent liquid and solids of the lower layer are drained. The brown organic solution is separated and pressure-filtered by a pressure filter or an electrodialysis (ED) method to obtain the final solid. The solid is added to an ethanol, methanol, isopropanol, or ethyl acetate solution for repeated rinsing and repeated filtration to remove impurities such as sulfuric acid, and then dried to obtain graphene oxide powder with a diameter of tens to hundreds of nanometers. The graphene oxide powder is rich in hydrophilic functional groups (e.g., oxygen atom percentage of 35-50%).

[0121] Example 2 - Synthesis of graphene oxide using sugar

[0122] A solid powder of 1-5 kilograms of monosaccharide, disaccharide, and / or polysaccharide, such as glucose, fructose, or sucrose, is added to 1 liter of deionized (DI) water, heated (to 50-80°C), and stirred to dissolve. The obtained warm solution is placed in a steel container. The steel container is sealed and then heated in a reaction furnace. When the steel container is heated to 160-220°C, the pressure in the steel container can reach 12-20 atm. After 2-5 hours of reaction, the steel container is cooled to room temperature, and the gas in the steel container is drained to release the gas pressure. The reaction product in the steel container is removed and dried to obtain a solid reaction product powder.

[0123] 30-60 liters of concentrated sulfuric acid with a concentration greater than 94% is added to a reactor with a polytetrafluoroethylene or glass coating lining. The reactor is cooled and kept at a constant temperature of about 0°C, the stirring is started, then 1 kilogram of reaction product powder is added, and the resulting mixture is stirred uniformly for 15 minutes to 1 hour, then 0.5-4 kilograms of potassium permanganate powder is slowly added to the mixture, and the mixture is controlled below 50°C, and the resulting mixture is stirred thoroughly for 15 minutes to 1 hour.

[0124] The reactor is heated to 40-50°C and kept constant, and stirring is continued for 0.5-3 hours, then the reactor is cooled to below 10°C and kept constant, and 30-60 kg of ice made of deionized water is added, and stirring is continued until the solution temperature is no longer fluctuating.

[0125] With continuous stirring, 6-30 liters of hydrogen peroxide is slowly added until the solution becomes yellow and no more gas is generated.

[0126] The solution is then subjected to pressure filtration through a pressure filter, or centrifugal separation at a speed of 2000-4000 rpm, or treatment by electrodialysis (ED) to obtain the final solid. The solid is added to an ethanol or methanol solution, subjected to repeated rinsing and repeated filtration to remove impurities such as sulfuric acid, and then subjected to drying treatment to obtain a graphene oxide powder with a diameter of tens to hundreds of nanometers and rich in hydrophilic functional groups (oxygen atom percentage of 35-50%).

[0127] Example 3 - Synthesis of graphene oxide using sugars and acids

[0128] Carboxylic acid, oxalic acid, citric acid, phosphoric acid, benzoic acid, dihydroxybenzene, and dopamine are added to deionized water along with a certain amount of monosaccharide, disaccharide, or polysaccharide (such as glucose, fructose, or sucrose) solid powder, and dissolved under stirring with heating (50-80°C). The obtained warm solution is placed in a steel container, which is sealed and then heated in a reaction furnace. When the steel container is heated to 160-220°C, the pressure in the steel container can reach 12-20 atm. After 2-5 hours of reaction, the steel container is cooled to room temperature, and the gas in the steel container is discharged to release the gas pressure. The reaction product in the steel container is taken out and added to an ethanol or methanol solution, subjected to repeated rinsing and repeated filtration to remove impurities, and then subjected to drying treatment to obtain a graphene oxide powder with a diameter of tens of nanometers to several microns and rich in hydrophilic functional groups (oxygen atom percentage of 30-40%). Figure 1A A transmission electron microscope (TEM) image of graphene oxide prepared according to Example 3 using sugars and acids is shown.

[0129] Figure 1B and Figure 1C An atomic force microscope (AFM) image of graphene oxide prepared according to Example 3 using sugars and acids is shown.

[0130] Example 4 - Synthesis of graphene oxide using multiple oxidation steps

[0131] First oxidation: Mix 1 kg of graphite powder with 30-60 liters of concentrated sulfuric acid (greater than 94%) and stir for 30 minutes at a constant temperature below 10°C. Add 5-10 kg of potassium permanganate powder to the mixture and stir for 15 minutes to 1 hour while cooling, then heat to 40-50°C for further reaction for 2-8 hours. After the reaction, recycle the remaining sulfuric acid and potassium permanganate solution (oxidant) through pressure filtration or vacuum filtration to obtain a solid reaction product powder. Then add the solid reaction product powder to 60 kg of ice and keep stirring until all the ice has completely melted and the powder is completely dissolved in the solution. Then add 2-4 liters of hydrogen peroxide to the solution and stir continuously until no more gas is generated in the solution. Then allow the solution to settle for several hours to allow precipitation or perform a centrifugation process to obtain the precipitate. Then dry the precipitate at 30-40°C to obtain a solid powder product: primary graphene oxide (GO).

[0132] Second oxidation: Add 1 kg of the pre-prepared graphene oxide to 60 liters of oxidant solution (a mixture of sulfuric acid and potassium permanganate in the same ratio as in the previous step), and disperse it using a ball mill or sonic bath. The diameter of the final obtained graphene oxide can be controlled by the amount of oxidant solution (60-300 liters).

[0133] Heat the uniformly dispersed solution to 40-50°C with stirring, and allow it to react for 2-8 hours. Then mix with 120-600 kg of ice and dilute with stirring. Add 2-20 liters of hydrogen peroxide to the solution and stir continuously until no more gas is produced.

[0134] The solution is then subjected to pressure filtration or electrodialysis (ED) to obtain solid graphene oxide. The solid graphene oxide is then added to a solution of ethanol, methanol, isopropanol, or ethyl acetate, and repeatedly washed and filtered to remove impurities such as sulfuric acid. It is then dried at 30-40°C to finally obtain graphene oxide powder rich in hydrophilic functional groups (40%-50% oxygen atoms), with diameters ranging from tens to hundreds of nanometers.

[0135] Example 5 – Characterization of graphene oxide

[0136] Particle size was compared using an electron microscope. For example... Figure 2A As shown, electron microscopy revealed the raw graphene oxide particles, with diameters ranging from hundreds of nanometers to tens of micrometers. Figure 2B As shown, when using approximately 180 liters of oxidation solution, the diameter of the graphene oxide obtained after the second oxidation process is 300-500 nanometers.

[0137] From top to bottom at 230 nm wavelength: raw graphene oxide, graphene oxide prepared using 120, 180, and 240 L of oxidation solution, respectively. The composition of the graphene oxide was characterized using UV-Vis spectroscopy.

[0138] like Figure 3 As shown, the composition of graphene oxide was characterized using UV-Vis spectroscopy. In the UV-Vis spectrum, the peak intensity of graphene oxide differed from that of virgin graphene oxide. Virgin graphene oxide exhibited a π-π* transition peak at 230 nm, which can be used as an indicator of its aromatic structure. The graphene oxide sample prepared in Example 4 showed a lower peak intensity at 230 nm than virgin graphene oxide synthesized using the conventional Hummers method. This is due to the smaller diameter and poorer aromaticity of the graphene oxide. Figure 3 The curves at a wavelength of 230 nm, from top to bottom, represent the initial graphene oxide and graphene oxide prepared using 180, 120, and 240 liters of oxidation solution. As the amount of oxidation solution used in the reaction increases, the particle size and oxygen atom percentage of the graphene oxide decrease.

[0139] Example 6 – Preparation of graphene oxide composite ultrafiltration membrane

[0140] Graphene oxide powder is added to organic solvents N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone (nano P) or dimethylformamide (DMF) and stirred. Then, monolayer or few-layer graphene oxide is uniformly dispersed in organic solvents DMAC, nano P, NEP or DMF, and the process is repeated at least three times using a high-pressure homogenizer at a pressure of 15,000-20,000 psi to obtain organic solution A containing dispersed graphene oxide.

[0141] Add graphene oxide powder to deionized water and stir. Then, uniformly disperse monolayer or few-layer graphene oxide in an inorganic solvent in deionized water and repeat the process at least three times using a high-pressure homogenizer at a pressure of 15,000-20,000 psi to obtain an inorganic solution B containing dispersed graphene oxide.

[0142] Figure 4The process of preparing graphene oxide composite ultrafiltration membrane is shown. Poly (vinyl pyrrolidone) (PVP molecular weight = 8-2000 kDa), triethyl phosphate (TEP), ethylene glycol (EG), polyethylene glycol (PEG) and perfluorosulfonic acid are added to the melt kettle together with solid particles of polyvinylidene fluoride (PVDF) and organic solution A containing dispersed graphene oxide. PVDF is a combination of various PVDF particles with a molecular weight range of 300000-700000. Then the mixture is heated and kept at a constant temperature of 40-70°C, continuously stirred for several hours until all raw materials are completely dissolved and uniformly mixed. After that, the solution from the melt kettle enters the spinning kettle and is degassed under negative pressure to remove bubbles at a constant temperature of 40-70°C, thereby obtaining a PVDF solution.

[0143] A dry-wet spinning process and a spinning system device are used to manufacture hollow fiber membranes (a dry-jet wet spinning process by non-solvent induced phase separation method through an intermittent wet spinning machine). The PVDF solution in the spinning kettle is extruded into water (pure water containing a certain amount of inorganic solution B) in the No. 1 coagulation tank at 5-30°C by compressed gas using a spinneret, and the extruded solution undergoes phase inversion into brown linear solids after contacting with water. Using a winding system, the linear solids are connected, slowly pulled out, and guided to soak in a mixed solution of methanol or ethanol and water in the No. 2 coagulation tank for a period of time, then slowly pulled out, and then sequentially immersed in the No. 3 reaction tank, the No. 4 reaction tank and the No. 5 washing tank in the same way for a period of time. The No. 3 reaction tank and the No. 4 reaction tank are aqueous or organic solutions composed of polyvinyl alcohol (PVA), glutaraldehyde, inorganic solution B containing dispersed graphene oxide, dichloromethane, octadecyltrichlorosilane (ODS) and hydrochloric acid (HCl). The No. 5 washing tank is a glycerol aqueous solution. The linear solids are taken out from the No. 5 washing tank to obtain the hollow fiber ultrafiltration membrane as the final product. Figure 5A and 5B is a scanning electron microscope (SEM) image of the cross-section of the graphene oxide-PVDF composite ultrafiltration hollow fiber membrane. Figure 5C and 5D is a SEM image of the surface of the graphene oxide-PVDF composite ultrafiltration hollow fiber membrane.

[0144] The inner diameter of the graphene oxide composite hollow fiber ultrafiltration membrane is 0.6-0.8 mm, and the outer diameter is 1.2-1.4 mm. The water contact angle of the membrane surface is 40°-60°. According to different chemical formula ratios, the membrane surface pore size can be adjusted between 10-100 nanometers; the porosity is 70-90%; the water flux is 400-600 LMH / bar.

[0145] Graphene oxide has a large number of hydrophilic functional groups on its surface and edges, such as carboxyl, epoxy and hydroxyl groups, so the connection of these groups with the surface of the polymer molecular chain can improve the hydrophilicity of the surface, increase the permeation efficiency of water, and can effectively prevent pollution caused by the adhesion and reproduction of organisms due to the low interfacial energy between the surface and water. In addition, the functional groups of graphene ensure a relatively high negative electric potential, which can also prevent the adhesion and accumulation of dust on the surface of the membrane. This can extend the service time or cleaning cycle of the ultrafiltration membrane by 2-5 times.

[0146] The hydrophilic functional groups can capture water molecules to form a water layer on the surface of the membrane, so that most lipophilic contaminants and bacteria cannot or are less likely to adhere to the surface of the membrane. Therefore, the antifouling property and recovery ability after backwashing of the entire membrane can be improved. Hydrophilicity can inhibit the hydrophobic-hydrophobic interaction between bacteria and the membrane surface. The negatively charged membrane surface can generate electrostatic repulsion to negatively charged bacteria and extracellular polymeric substances (EPS).

[0147] Example 7 - Preparation of another graphene oxide composite ultrafiltration membrane

[0148] Figure 6 The process of preparing a second graphene oxide composite ultrafiltration membrane is shown. 10-25wt% of polysulfone (PSU), poly(oxybenzene sulfone), polyetherimide (PEI) and polyether sulfone (PES) are added to the melt kettle together with a certain amount of polyethylene glycol (PEG) and organic solution A containing dispersed graphene oxide. The polysulfone is a combination of various polysulfone particles with a molecular weight range of 67,000-81,000. The mixture is then heated and kept at a constant temperature of 40-70°C, continuously stirred for several hours, until all the raw materials are completely dissolved and uniformly mixed. After that, the solution is degassed under negative pressure to remove air bubbles at a constant temperature of 40-70°C, thereby obtaining a polysulfone solution.

[0149] A polypropylene non-woven support layer is pre-wetted using an organic solvent, N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone (NMP), or dimethylformamide (DMF), and then a polysulfone solution is coated on the non-woven surface using a microfilm applicator or a casting knife. The coated non-woven is then immersed in a 5-30 °C water (pure water containing a certain amount of inorganic solution B) in a coagulation tank No. 1 for soaking, during which the polysulfone solution is solidified by phase inversion to produce an ultrafiltration membrane layer on the non-woven surface. The membrane is taken out, the excess liquid is removed from the membrane surface with an air knife, and the membrane is dried in an oven at 40-60 °C, and then the dried membrane is immersed again in a solution in a reaction tank No. 2. The solution is composed of polyvinyl alcohol (PVA), glutaraldehyde, inorganic solution B with dispersed graphene oxide, dichloromethane, octadecyltrichlorosilane (ODS), and hydrochloric acid (HC1). The immersed membrane is taken out, the excess liquid is removed from the membrane surface with an air knife, and then the membrane is immersed again in a methanol or ethanol and water mixed solution in a washing tank No. 3 for soaking and cleaning. The cleaned membrane is taken out, the excess liquid is removed from the membrane surface with an air knife, and the membrane is dried by baking in an oven at 40-60 °C, and then the membrane is immersed again in pure water in a washing tank No. 4 for soaking and cleaning. Finally, the cleaned membrane is taken out, the excess liquid is removed from the membrane surface with an air knife, and the membrane is dried by baking in an oven at 40-60 °C to obtain the final product, a planar ultrafiltration membrane. The water contact angle of the membrane surface of the graphene oxide composite planar ultrafiltration membrane is 40-60°. According to different chemical formula ratios, the membrane surface pore size can be adjusted between 10-100 nm; the porosity is 70-90%; and the water flux is 400-600 LMH / bar. Figure 7A and 7B are scanning electron microscope (SEM) images of the membrane surface at two different magnifications.

[0150] Example 8 - Preparation of graphene oxide composite nanofiltration membrane

[0151] Figure 8 A method for preparing a graphene oxide composite nanofiltration membrane is shown. Poly(vinylpyrrolidone) (PVP molecular weight = 8-2000 kDa), triethyl phosphate (TEP), ethylene glycol (EG), polyethylene glycol (PEG), and dopamine are added to a melting kettle together with 15-30 wt% of polyether sulfone (PES) solid particles and organic solution A with dispersed graphene oxide. The polyether sulfone is a combination of various polyether sulfone particles with a molecular weight range of 45000-68000. The mixture is then heated and kept at a constant temperature of 40-70 °C with continuous stirring for several hours until all raw materials are completely dissolved and uniformly mixed. After that, the solution goes from the melting kettle to a spinning kettle and is degassed under negative pressure to remove air bubbles at a constant temperature of 40-70 °C to obtain a polyether sulfone solution.

[0152] Hollow fiber membranes were manufactured using dry-wet spinning process and spinning system apparatus (dry-jet wet spinning process using a spinning system). A polyethersulfone solution in a spinning kettle was extruded through a spinneret into water (pure water containing a certain amount of inorganic solution B) of 5-30°C of No. 1 coagulation tank by compressed gas, and phase inversion to brown linear solid occurred after the extruded solution contacted with water. Using a winding system, the linear solid was connected, slowly pulled out, and guided to soak in a mixed solution of methanol or ethanol and water in No. 2 coagulation tank for a certain period of time, and then slowly pulled out, and then sequentially soaked in No. 3 reaction tank, No. 4 reaction tank, and No. 5 washing tank in the same manner for a certain period of time. No. 3 reaction tank and No. 4 reaction tank were aqueous or organic solutions composed of polyvinyl alcohol (PVA), glutaraldehyde, inorganic solution B in which graphene oxide was dispersed, dichloromethane, octadecyltrichlorosilane (ODS), and hydrochloric acid (HC1). No. 5 washing tank was a glycerol aqueous solution. The linear solid was taken out from No. 5 washing tank to obtain a hollow fiber nanofiltration membrane as a final product.

[0153] The inner diameter of the graphene oxide composite hollow fiber nanofiltration membrane was 0.6-0.8 mm, and the outer diameter was 1.2-1.4 mm. The water contact angle on the membrane surface was 40-60°. According to different chemical formula ratios, the membrane surface pore size could be adjusted between 1-10 nm; the water flux was 20-120 LMH / bar.

[0154] Example 9 - Preparation of another graphene oxide composite nanofiltration membrane

[0155] Figure 9 A method for preparing a second graphene oxide composite nanofiltration membrane is shown. Poly (vinyl pyrrolidone) (PVP molecular weight = 8-2000 KDa), triethyl phosphate (TEP), ethylene glycol (EG), polyethylene glycol (PEG), and dopamine were added to a melting kettle together with 15-30 wt% of polyethersulfone solid particles and organic solution A in which graphene oxide was dispersed. The polyethersulfone was a combination of various polyethersulfone particles having a molecular weight range of 45,000-68,000. Then the mixture was heated and maintained at a constant temperature of 40-70°C with continuous stirring for several hours until all the raw materials were completely dissolved and uniformly mixed. Thereafter, the solution from the melting kettle entered a spinning kettle and was degassed under negative pressure to remove air bubbles at a constant temperature of 40-70°C to obtain a polyethersulfone solution.

[0156] The polypropylene non-woven support layer is pre-wetted using organic solvent N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone (NMP) or dimethylformamide (DMF), and then the polysulfone solution is coated on the non-woven surface using a microfilm applicator or a casting knife. The coated non-woven is then immersed in a 5-30 °C water (pure water containing a certain amount of inorganic solution B) in a No. 1 coagulation tank for soaking, during which the polysulfone solution is solidified by phase inversion, thereby generating a nanofiltration membrane layer on the non-woven surface. The membrane is taken out, the excess liquid is removed from the membrane surface using an air knife, and the membrane is dried in an oven at 40-60 °C. The dried membrane is then immersed again in a solution consisting of polyvinyl alcohol (PVA), glutaraldehyde, inorganic solution B with dispersed graphene oxide, dichloromethane, octadecyltrichlorosilane (ODS) and hydrochloric acid (HC1) in a No. 2 reaction tank. The immersed membrane is taken out, the excess liquid is removed from the membrane surface using an air knife, and the membrane is immersed again in a methanol or ethanol and water mixed solution in a No. 3 washing tank for soaking and cleaning. The cleaned membrane is taken out, the excess liquid is removed from the membrane surface using an air knife, and the membrane is dried by baking in an oven at 40-60 °C, and then immersed again in pure water in a No. 4 washing tank for soaking and cleaning. Finally, the cleaned membrane is taken out, the excess liquid is removed from the membrane surface using an air knife, and the membrane is baked and dried in an oven at 40-60 °C to obtain a planar nanofiltration membrane as the final product. The membrane surface water contact angle of the graphene oxide composite nanofiltration membrane is 40-60°. According to different chemical formula ratios, the membrane surface pore size can be adjusted between 1-10 nanometers; the water flux is 20-120 LMH / bar.

[0157] Example 10 - Preparation of graphene oxide reverse osmosis membrane

[0158] The graphene oxide reverse osmosis membrane can have a graphene oxide composite ultrafiltration membrane support layer (e.g., using the same method as in Example 7) and a graphene oxide composite polyamide selective layer.

[0159] The graphene oxide powder is added to hexane, isoparaffin, light alkylated naphtha or cyclohexanone or organic solvent alkane such as cyclohexanone and stirred, and then the single-layer or few-layer graphene oxide is uniformly dispersed in the organic solvent alkane or cyclohexanone such as hexane, isoparaffin, light alkylated naphtha or cyclohexanone, and an organic solution C with dispersed graphene oxide is prepared by repeating at least three times using a high-pressure homogenizer at a pressure of 15000-20000 psi.

[0160] Figure 10A method for preparing a graphene oxide composite polyamide selective layer is shown. 1-4 wt% of triethylamine (TEA), 1-5 wt% of camphor sulfonic acid (CSA), 0.5-6 wt% of m-phenylenediamine (MPD), a certain amount of dimethyl sulfoxide (DMSO), 2-ethyl-1,3-hexanediol (EHD), sodium lauryl sulfate (SLES), 2-ethylhexanol, dioctyl fumarate, di(2-ethylhexyl) adipate, polyethylene glycol (PEG), octanoic acid, 1,2,3-propanetricarboxylate, dioctyl phthalate, dimethyl silicone oil, ethanol, methanol and isopropyl alcohol are added to the inorganic solution B dispersed with graphene oxide, respectively, to obtain solution D.

[0161] 0.01-0.2% of 1,3,5-benzene tricarboxylic acid chloride (TMC), 0.1-0.5 wt% of tributyl phosphate (TBP) and the organic solution C dispersed with graphene oxide are added to an alkane or a cycloalkane ketone such as hexane, isoparaffin, light alkylated naphtha or cyclohexanone, and are fully dissolved under stirring to obtain solution E.

[0162] The graphene oxide composite ultrafiltration membrane is immersed in solution D of the 5th reaction tank for thorough soaking, then taken out, and then the excess solution D on the surface of the membrane is removed using an air knife or a butadiene rubber roller, and then the ultrafiltration membrane is immersed in solution E of the 6th reaction tank, so that the solution D in the gap of the ultrafiltration membrane diffuses to the surface of the membrane to contact with the solution E and carry out an interfacial polymerization reaction to form a graphene oxide composite polyamide selective layer.

[0163] The membrane is taken out from the 6th reaction tank, and then immersed in an organic solvent alkane or cycloalkane ketone such as hexane, isoparaffin, light alkylated naphtha or cyclohexanone in the 7th washing tank for soaking and cleaning, followed by drying by baking in an oven at 40-60°C, and then again immersed in a certain concentration of sodium hypochlorite NaOCl and Na2CO3 aqueous solution in the 8th tank and pure water in the 9th tank for soaking and cleaning, and dried by baking in an oven at 40-60°C, to finally obtain a flat reverse osmosis membrane as a final product.

[0164] The membrane surface water contact angle of the graphene oxide composite reverse osmosis membrane is 40-60°. When a 2000 ppm sodium chloride solution is used, the water flux is as high as 3-5.4 LMH / bar at a pressure of 15.5 bar; the desalination rate is as high as 99%.

[0165] Graphene oxide has a large number of hydrophilic functional groups on its surface and edges, such as carboxyl, epoxy and hydroxyl groups, which can significantly improve the surface hydrophilicity, electronegativity and surface smoothness of the membrane, so the graphene oxide enhanced membrane has higher water permeability. In addition, the hydrophilic functional groups can capture water molecules to form a water layer on the membrane surface, and by cooperating with the improved surface smoothness, lipophilic contaminants and bacteria cannot or are less likely to adhere to the membrane surface. Therefore, the antifouling property and recovery ability after backwashing of the entire membrane can be improved. In addition, the functional groups of graphene ensure a relatively high negative electromotive force, which can also prevent dust from adhering and accumulating on the membrane surface. This can extend the service time or cleaning cycle of the ultrafiltration membrane by 2-3 times. Figure 11A 、 Figure 11B and Figure 11C are SEM images of the surface of the graphene oxide composite reverse osmosis membrane at three different magnifications.

[0166] While preferred embodiments of the application have been shown and described in the present application, it will be apparent to those skilled in the art that these embodiments are provided only by way of example. Many variations, changes and substitutions will occur to those skilled in the art without departing from the application. It should be understood that various alternatives to the embodiments of the application described herein can be employed in practicing the application. The following claims are intended to define the scope of the application and thus encompass methods and structures within the scope of these claims and equivalents thereof.

Claims

1. A method for preparing graphene oxide, comprising: a) mixing a sugar component and an acidic component to obtain a mixed component, the sugar component comprising monosaccharide, disaccharide, polysaccharide, or any combination thereof, the acidic component comprising carboxylic acid, oxalic acid, citric acid, phosphoric acid, benzoic acid, dihydroxybenzene, dopamine, or any combination thereof; and b) heating the mixed component to produce a composition comprising graphene oxide, wherein the graphene oxide has an average particle size of no more than 1 micron and a molar percentage of oxygen atoms of 30-40%, and the sugar accounts for 1-60% of the composition comprising graphene oxide by mass percentage; the method further comprising: adding the sugar component and the acidic component into deionized water and stirring to dissolve at 50-80°C to obtain a warm solution of the mixed component; reacting the warm solution at 160-220°C and a pressure of 12-20 atm for 2-5 hours to obtain a reaction product; adding the reaction product into an ethanol or methanol solution, repeatedly rinsing and filtering to remove impurities, and then drying to obtain the graphene oxide.

2. The method of claim 1, wherein, the sugar component comprises glucose, fructose, sucrose, or any combination thereof.

3. The method of claim 1, wherein, the method further comprising: mixing the graphene oxide with a first organic solvent to obtain a first organic solution comprising the graphene oxide; mixing the graphene oxide with an inorganic solvent to obtain an inorganic solution comprising the graphene oxide; mixing the first organic solution with a polymer to form a polymer solution; mixing the polymer solution with water containing the inorganic solution to produce a solid; based on the solid, generating a water filtration membrane.

4. The method of claim 3, wherein, the first organic solvent comprises N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethylformamide, or any combination thereof.

5. The method of claim 3, wherein, the polymer comprises polyvinylidene fluoride or polysulfone.

6. The method of claim 3, wherein, the water filtration membrane is a composite ultrafiltration membrane having a porosity of 70-90%, a water contact angle on the membrane surface of 40-60°, a membrane surface pore size of 10-100 nm, and a water flux of 400-600 LMH / bar.

7. The method of claim 3, wherein, the polymer comprises polyethersulfone.

8. The method of claim 3, wherein, the water filtration membrane is a composite nanofiltration membrane having a water contact angle on the membrane surface of 40-60°, a membrane surface pore size of 1-10 nm, and a water flux of 20-120 LMH / bar.

9. The method of claim 3, wherein, the method further comprising: mixing the graphene oxide with a cycloalkanone or an organic solvent alkane to obtain a second organic solution comprising the graphene oxide; mixing triethylamine, camphorsulfonic acid, m-phenylenediamine, dimethyl sulfoxide, 2-ethyl-1,3-hexanediol, sodium lauryl sulfate, 2-ethylhexanol, dioctyl fumarate, di(2-ethylhexyl) adipate, polyethylene glycol, octanoic acid, 1,2,3-propanetricarboxylate, dioctyl phthalate, dimethyl silicone oil, ethanol, methanol, isopropyl alcohol, or any combination thereof with the inorganic solution to obtain a first solution; mixing 1,3,5-benzene tricarbonyl chloride, tributyl phosphate, or any combination thereof with the second organic solution to obtain a second solution; The water filtration membrane is sequentially immersed in the first solution and the second solution to form a graphene oxide composite polyamide selective layer on the surface of the water filtration membrane, thereby generating a graphene oxide composite reverse osmosis membrane.

10. The method of claim 9, wherein, The membrane surface water contact angle of the graphene oxide composite reverse osmosis membrane is 40-60°, the water flux is 3-5.4 LMH / bar under a pressure of 15.5 bar when a 2000 ppm sodium chloride solution is used, and the desalination rate is 99%.

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